Nap transition

It’s been a couple weeks now since my son decided he was ready for one nap instead of two during the day.. only problem is he will only nap for like an hour sometimes a little less sometimes a bit more. I will rock him on the back end because there’s noooo way I can deal with a baby who’s only taken one one hour nap for an entire day 😅 but ideally I don’t want to rock him everyday to get him to sleep longer, but idk how else to extend his naps... I’ve tried to let him cry and check on him but after the 45 min mark I called it and rocked him.

Any tips or advice would be appreciated