If all is working as designed regen will occur as needed (ecm monitors soot load). On the Rams if all is working as designed, and you don’t drive the pickup in a manner that allows regen, you’ll eventually see a message that directs you to remain driving until regen complete.

Check engine light on? Some codes suspend regeneration and this more times than not, will cause more issues to those that keep on driving in hope that it will just get better on its own.

Idle time... never a good thing, but sometimes a necessary evil. Newer rigs engine running in park you can turn the cruise on, push set and “+” and ramp the idle up to 1500 rpm.