As others have noted above, the problem is not the pedals.
First time...You should have switched to a lower gear before climbing the hill.
2nd time..Sounds like the derailleur is out of adjustment meaning the chain should not have fallen off of the lower ring.
3rd time...I got nothing on that one. That's just user error.
Anyway if you are ok with giving up a little efficiency and just want to ride, then flat pedals are for you.
Otherwise, check out the Time pedals with 10 degree easy release cleats. It's what I use due to bad knees from some past ACL injuries in both knees
.
https://www.sram.com/en/time-sport/m...d-atac-eclt-a1
https://www.sram.com/en/time-sport/r...levancy&page=1