Putting baby for a nap

I wanted to ask your advice regarding naps. My baby naps in a stroller as then I have ability to move the stroller back and forward in case baby starts getting fussy and potentially wake up. This way, I prolong his naps, however the he will soon outgrow stroller’s bassinet and I think it’s time for him to sleep in his crib.. but how will I help in sooth himself while he is the crib without sleep training? How are you putting your LOs for a nap?:)

P.S. Baby sleeps through the night in his crib - no problem here, just issues with nap time.