Hello and welcome
At night, do you think it could possibly be reflux bothering him? That can often look like gassiness and would cause frequent wakings due to pain. Feeding soothes the pain temporarily if that is the case. There is some info about reflux here:
Reflux 101 - General reflux information. Have you chatted to your doctor about it whatever the problem is?
Have you ever tried settling at night without a feed? Shh pat? Paci?
Yawning after waking up can be still tired, or just what he does when he wakes. I've never personally found it a very reliable tiredness sign in terms of knowing when to put down for naps.
He's quite young for PUPD really, I would stick with shh pat (especially if there is a chance his discomfort could be reflux). 40 minute naps could be developmental in that he hasn't yet learned to transition through sleep cycles independently, it's always easier for LOs to stay asleep with motion in the pram/car. If he is going to sleep independently at the start of naps it may be a case of waiting until he learns that skill. If he sleeps 40 minutes in bed can you ever resettle him? 1h45 is about the right A time for his age, maybe a touch long but some LOs can handle it ok. After a short nap you may need to get him down a bit sooner though as overtiredness will build up during the day making it harder for him to settle.
E time is start of one feed to start of next - so 7/10/1/4/7 would be a 3h EASY.