I have a 2020 Jeep with the 3.6 I bought new and 2017 Journey with it also.....I bought used with 14k miles ....I use 5w20 QS syn in both now and Mopar filters....and change at 5k
I have ran Pennzoil, Napa, Havoline, and now Valvoline whatever Synthetic on sale. I am sticking to Valvoline. Normally I run Severe duty which is around 4k which according to the hour meter is about right.