it's a bit tricky to see what's happening in your routine at the moment
7:20 - 7:30am: nap
I assume these are the times you are putting him down for a nap - could you post your EAS times showing the time he goes to sleep and the time he wakes up please? Something like this:
S 7.30 - 8.15
A 1hr 15
S ...and so on
This would help us to see where a change in times might be helpful for you.
You are approaching, or possibly arrived at, the move towards 4hr E. Tracy said LOs move to the 4hr EASY during the 4th month.
If your LO is feeding better with 3.5hr E then that's fine. Also fine to cluster in the evening before BT. You might find on the lower A time and with shorter naps plus with the E time extending, that you are getting clashes with the E and S times, for instance if LO wakes at 8.15am after a 45 min nap the next nap is due at 9.45am (1hr 30 A time) but E is due at 10am (3.5hr E) in cases like this you might need to feed early (say 9.15) and just do a minute or two A time before the nap. It could be that if you put LO down for a nap without the early E he might make it until the end of the nap and that might not be so bad if he only sleeps 45 mins (E then at 10.30) but if he slept longer the E times extend a bit too much.
The guidance A time is approx 1hr 30 for 3 months old. It could be that you just need to increase the A a bit to get some better naps - but like I say it's hard to tell really until I see how long each nap is. You can also add to your EAS times some notes about mood such as crying on entering the bedroom or nap refusal, or waking happy/crying from naps.