Mouse Freezes on Secondary, won't switch to Primary

Setup

I have 2 Windows 10 PCs (primary Win10 Home 22H2, secondary Win10Pro 21H1) in seamless mode and 1 Windows 11 PC set up in full remote KVM mode. No issues with the full remote KVM, since lag only occurs during heavy load, which is expected. The 'seamless' device (hereto: "secondary") is set up to use a keybind to swap devices and share my dual-monitors via input switching (manual, buttons on screens). Keyboard/mouse connected to primary, with a wireless set connected to the secondary turned off. THIS has serious issues.

Issue

While controlling the secondary device I experience unpredictable lag from the cursor. Neither computer is under heavy load when using the secondary since it's only used during work hours. But that lag is a minor issue compared to multiplicity locking up entirely. The mouse cursor freezes in place and no amount of trying to switch inputs or waiting will unfreeze it. Ctrl+alt+del luckily still works for the primary and has mouse control when on that screen but will revert to frozen in the secondary when not in that menu. Locking the devices will not recover mouse control. I have to sign-out on the primary to force multiplicity to close (losing any work I had open).

Having the wireless keyboard/mouse on hasn't solved the issue. Fake pointer support is off. Firewall ports are opened and the MPPortFix file was run to verify.

Any knowledge of how to prevent this freezing would be helpful. I would like to use the program reliably so I can fully separate my gaming (primary) and work (secondary) device.