Regen issue

Hello, I have a 2015 Volvo d13. It's asking for a parked Regen almost daily. Has an all new def system, including pressure differential sensor and doser.

It never gets to active Regen. I can watch the soot level gauge go from nearly empty to level 2 in a heartbeat after about 6 hours of highway driving. Just boom full.

I was thinking soot level sensor, as I've already done the pressure differential.

Also maybe another related problem, cab low voltage alarm going off randomly. Smack the dash by the radio and it turns off every time. Checked all the wiring back there but can't find nothing. Thinking it might be the actual radio going out and drawing too much voltage. But the Regen issue is what's really bothering me right now.