Crying when tired

Our little one is like this. If she is over tired she will scream until she exhausts herself and falls asleep. We now try to watch how long she has been awake and start to get her to try nap when we think she is going to need it x

You need to catch on earlier sleep cues before he starts screaming !
My first baby was like this and when I learnt his sleep cues it was so much easier x

My 3 month old has always been fine having a nap but the past week she is really fighting her naps and crying when she can tell we are trying to settle her x

We have recently realised that our 3m old has increased his wake period, meaning that when we were trying to put him to sleep he wasn't tired enough and he was crying and screaming himself to sleep. We used to put him to sleep after 1h -1h 20min. Now we put him after 1.5h - 1h 50 min and it became much less of a struggle.
Now.. it could be that your son is either too tired as you said, or being fussy for a short period until he actually wants to be put to sleep.
If only they could talk 😅😅