3.5 y/o sleep/nap struggles. Read fiest please! Would you encourage naps or try to keep them awake?

So my 3.5 year old son was napping well 1230/1-2/3 until he was about 2.5 then started fighting naps a few months from turning three (conveniently right after his brother was born, when I was banking on those naps) until 2/3pm and I would wake him at 3 or 315 to make sure we didn’t have a horrid night routine (it was ROUGH for a while, I really didn’t want to let that nap go. Well I stopped really making him lay down after he turned 3 in dec and here and there he’s been trying to put himself to bed at 4-6pm since I stopped fighting him for the nap, but generally it’s a one off and he gets through the day most days. If we drive though he almost always falls asleep. I’d say the last week he has been falling asleep at 2/3 again for maybe 15-20 minutes (I let him have a little bit of a rest if he was tired enough to fall asleep) and our nights have been horrible. He fights me to go to sleep until 9/10 and then is up one or two times in the night, whereas when he doesn’t get a short nap he goes down at 8 pretty easily and sleeps till 630/730. I feel bad waking him when he falls asleep but it’s almost seeming like i have to if I want to get a decent nights sleep. Does anyone else have to do this? What has anyone done that helped? I just don’t know what to do. Feel bad waking him as if he’s asleep I would guess his body needs it. Pic of how he fell asleep today lol. I feel like it’s all a mess so if you made it through and that somewhat makes sense to you, thank you and please kindly advise, sincerely a very sleep deprived mom haha.