4 month old- struggling but seeing improvements?

We started sleep training a week and a half ago. Tried Ferber but he cried much harder with check ins, so switched to CIO. We are doing nap training and bedtime training at the same time.

Problem #1: Baby falls asleep for naps in seconds, no crying. Easy. The problem is, he only sleeps for 30 minutes max. I keep trying crib hour but i find it frustrating for both me and baby as he just cries the rest of the hour with no signs of falling back asleep.

I wanted to switch to 3 naps so he can have consolidated sleep. But because of the thirty minute naps, we are at 4 naps. I don’t know if I should accept 30 minute naps for now or just keep trying crib hour. I hate hearing him cry for the remainder of the 30 minutes.

Ive tried extending wake windows, reducing, etc. Nothing seems to lengthen the naps. Except for stroller walks when he needs a rescue nap. He can nap 2 hours in the stroller no problem. But, I don’t want to keep doing stroller walks because we need to keep practicing crib naps.

Problem #2: A week and a half in, and baby still cries up to an hour before bedtime, screaming on and off till finally falling asleep. One day we had a 20 minute cry before bed. So, he usually falls asleep at 8pm or a bit after. But baby sleeps well through the night, waking at midnight and 3 am for feeds and falling back asleep till 7/7:30 am, when I have to wake him up for the day.

I have been doing 2 hour wake windows through the day. Before bedtime, I stretch to 2.5 hours.

Baby is up by 7:30 am for the day. I put the baby down between 7-7:30 pm for the night, depending on the last nap.