A lot of plugins do network connections for “phoning home”…
Cubase12 also has some local network connections open, to communicate with the license engine if I’m not mistaken.
Those usually shouldn’t be a big problem, as they happen in the GUI threads and not in the DSP threads.
Can’t tell you what your problem is, could be an issue with the Focusrite driver, could be a plugin (I just yesterday had a buggy plugin that would immediately bring the audio to a halt when inserted…).
Are your problems directly correlated to switching the audio device driver? I.e. switching back to your tascam will fix the problem? Then I’d suspect the focusrite.
If it is only happening in this one project, it could be a plugin.