Do you guys cap naps?

Do you cap your LOs nap? And if so, when?

My little guy usually wakes up about 7:30 and goes down for a nap between 12:30-1 and sometimes will sleep up to 3 hours, however I will wake him up by 4 if he tries to sleep that long or if he went down for his nap a little later than usual. Here lately he doesn’t want to go down for bed time and I’ve even pushed bedtime back by about 30 minutes. I’m not sure if him fighting bedtime is due to me letting him nap too long or if he’s hitting the 18 month sleep regression 😬