I solved my problem so this is just a heads up if someone else happens to bump in to the same issue. I recently moved from Raspberry Pi 3 to X86 based Udoo X86 Ultra minipc for my imaging and for some reason my setup which had worked fine previously just didn't anymore. I use Atik 383L+ for imaging and Lodestar X2 for guiding and the Lodestar always stopped responding a while after starting a sequence and didn't recover until powered down and up again. Today I noticed that it always happened during image download from the Atik and I remembered there was a difference in buffer size for the Atik between ARM and X64 builds and lo and behold, dropping the buffer size from 24 MB to 8 MB like it is on the ARM made everything work again. I don't know if the root cause is that they are both behind the same StarTech USB 3 hub or not, but at least this way everything works again.
Remote observatory running Ubuntu 20.04 x64 with ScopeDome 2M, Skywatcher EQ8, TS 8" RC, Atik 383L+, ASI178MC, ASI120MM-S, SX Lodestar X2, SX USB wheel with OAG, ZWO EAF, Gemini SnapCap, USB_DewPoint, KomaHub