I would suggest checking your shock settings first if it’s a full suspension bike. I’m also about 220, (well maybe closer to 230) and long legged like a gazelle. If you haven’t installed any volume reducers yet, do that before you change your cranks. It’s possible you are just blowing through the stroke too easily from to soft of a spring rate causing more pedal strikes. Just adding more air does not fix this problem, assuming it is an air shock.
As far as crank lengths go I think the 5mm makes a big difference. Both in how the bike pedals and seat position, a shorter crank will mean a slightly higher seat and an adjustment to move the seat back.
I have found the Koobi PRS Enduro saddle to be very comfortable. It’s soft enough to be comfortable and firm enough to not sink into the saddle, also easy to move around on. This saddle also has changeable, different firmness elastomers that you can use depending on your weight that take up the harshness when seated. It’s been a great saddle for many thousands of miles. They also have a great return policy, 100% up to 30 days, 60% up to 60 days, and 30% up to 90 days. This saddle does take some time to break in so it’s not as comfy the first 10-20 hours on it. My wife even uses the same saddle just with different elastomers. She didn’t like any of the saddles we could find until I made her try mine. Didn’t mean for this to sound like an ad but I really like mine.