Culture upgrades can be risky in that it limits your defensive abilities later on...however, they can also force your enemy to build more culture centers and less trade ports/factories...

In general, I find that culture SBs are only useful if the nearby enemy planets are asteroids...since asteroids can only have 3 logistic structures, being forced to build extra culture centers can limit your enemies ability to extend their trade route or have factories on the frontline...planets with more logistic slots won't be hit as hard...

which factions strikecraft are better overall?

which factions fighters beat each other 1-on-1?

it appears that advent has more squad members but weakest individual ships, vasari has the least members but best individuals, and tec is in the middle

i personally prefer vasari since their health makes them less vulnerable to flak bursts/telepush and they have phase missiles

In terms of the balance of health and damage, they're mostly the same.  The biggest difference is that Vasari use phase missiles for both fighters and bombers, which gives them a tremendous advantage when attacking frigates, cruisers, capital ships, and starbases.  The only place they're weaker is in fighter vs fighter, but this isn't actually as important as it may seem, since Vasari also has the best flak for bringing down enemy fighters.

It's definitely not as good, but on the other hand Advent turrets benefit a lot from the shield bestowal of their hanger.  Usually people use synergy turrets as an alternative to weapons upgrades for their starbase, freeing up slots for other purposes.

The real disadvantage of Advent beam platforms is that you need several of them to receive much of a benefit (hence "synergy")...even one or two TEC/Vasari point defenses are useful since meson bolt/disrupter nanites make for good focus firing...Advent beam platforms however don't provide the same FFing capabilities unless there are tons of them...

The answer is still bombers. Flak to protect your own fleet and use your bombers to nuke the hangars then the SB. What faction are you playing? If Advent then TK push to defend your caps and shield bubble  over the battle ball.  If Vasari then abuse scramble bombers. You can also sacrifice a subverter or two to reduce shield mitigation then use an Egg for a final kill with the armor reducing ability (risky). For flak one option is to send them along the path the bombers take from the Argonev.You can also have your flak follow your HCs around while they kill the rest of the orbital structures. If you are worried about some units meandering towards the SB then use hold position. Your own fighters should torch the bombers also. How many strikecraft are you attacking with?

If you're the TEC, you can also take some Ogrovs and pound it from afar. If you're really paranoid, you can take an Akkan with Targeting Uplink to give them more range, and if you happen to have Tier 7 military techs available, you could research Extended Range Missiles for an extra 4%/8%/12% range. With that much range boost, even Javelis LRMs can join in and add their fire.

Seleuceia brings up a key point. Is this vs AI or a human player? If AI then people (including myself) have offered multiple solutions and you don't need to fear the red button. If human then either a) bring enough bombers or ogrovs (if TEC) or go around and avoid the starbase completely. You can always strip the rest of the grav well like locusts and then move on.

The strikecraft from the Argonev should not bother you much while you pillage his orbital structures if you have enough flak and properly position them. Most human players put the SB right at the edge of the phase lane to trap you after a jump, so beware the red button. But if you scout well enough you can usually (I stress usually) go around.

Personally I fear an Orkulus backed by hangars with phasic trap much more than an Argonev. ANd if it is also supported by a  fleet with supporting overseers and subverters then it is time to pull out a Kostura else gg. Transcencias can also massively suck with the huge range of mass disorientation and meteor control. If I ever see a human player with a Transcencia fully loaded with strikecraft I will get up and do a little happy dance since it means he completely messed up his upgrade choices.

i encountered essentially the same situation in a different game. i'm sure that with enough bombers and no opposition i could eventually whittle through the base, but i only had 19 (and 10 fighters, because flak would get killed by the sb if they tried to chase their fighters), and they brought their fleet in before i could even take down its shields. the problem is that i couldn't get another fleet supply upgrade because my 5-planet economy was already low, and the ai had a larger empire than me. it had made allies with one of the other ais in the system, while the fourth one was hostile to everybody. i also couldn't move on to the next planet because all my ships would lose half their hp and all of their antimatter.

ok, i'm tired of this cruel bs. it's always the same, no matter how many times he attacks and i destroy his fleets, he just builds a new one while hiding behind his impenetrable minefield+starbase defense which i can't breach without killing myself with upkeep. meanwhile im stuck with 5 planets and can't attack or go for the neutral system. it also doesn't help that my stupid flaks decide to drive into the heart of the enemy formation and my guardians are always out of antimatter or being crippled by cobalts.

There are different ways to manage fleets.  If you are breaking into a hostile gravity well with mines, heavy defenses, and a starbase, I suggest you have your entire fleet in "hold position" and you manually control their movement.

After repulsing a big AI fleet and weakening them enough to start an offensive, take a corner of the enemy gravwell and let them come to you.  Use your firepower and flak defensively while using bombers to pick apart the defensive positions.  Have scouts with your fleet so as you inch forward, your fleet destroys the mines that the scouts detect.  If you think you will get overrun by newly built reinforcements, construct your own starbase to hold your corner of the gravwell and keep your fleet by it.

Eventually you will destroy enough defenses and ships that your fleet will be free to assault the enemy starbase and then take the world.  You will have to inch forward world by world this way until the AI finally doesn't have the econ to support a defense and you start to steamroll.

The main thing is try to fight defensively, even in the enemy gravwell, and not let your ships run around and get picked off by defenses.