Some great advice there from Sarah!
I agree he's showing signs he needs to go longer between feeds now. What I would suggest is if you would normally feed at say 2.5h, next feed just distract him or put it off for an extra 15 mins. No more, this isn't about doing huge jumps or starving him, just aim to get to 2.75h before you feed. Once you've done it, you know he can! So then if you do one or two feeds like that, next time just add another 15 mins and you're already at 3h! I was surprised when I did this that often LO would be totally happy for way longer than I expected, and it took really no time at all to get to 4h. Sarah's completely right that not all EBF babies will manage 4h but see how far you get with this way of extending the time - he may just surprise you!
In terms of routine, with short naps you have two choices: try to resettle and extend, or just go with it. Pick the option that causes YOU least stress
. If you choose to go with short naps for now, I would focus on keeping the feeds well-spaced and then just do more naps in a day. You'll need to have an EASAS or AEAS pattern at certain times as Sarah suggested - just try to plan ahead as much as you can to avoid eat/sleep clashes.
If you decide to go with PUPD, it can be very effective but only if used in conjunction with an age-appropriate routine. If the A times are wrong, no amount of PUPD will send LO back off to sleep again. It's also important you do it in an age-appropriate way -
How to PU/PD (inc age adaptations) - and at 4 months that will be primarily shh pat and soothing in the crib.
Did you want to post a recent or typical day to see if we can make any suggestions?