I think many of us when we were kids have had experience hunting with our BB guns at 3 fpe and pellet guns (mine was around 8 fpe) as far as killing small game. Well small game can be a sparrow or mouse, or critters the size rabbits. We found out that head shots weren't easy and often body shots resulted in wounded critters that flew or ran off. Most of my shots were inside 25Y and 25Y was a long way off back then.
I bring this up because I feel like using as much energy as you can get away with helps in putting critters DRT. 20-30 fpe seems like a sweet spot at normal airgun distances. It's enough power without going too crazy. I mean crazy in a good way, lol, but the downside is the more power you have the more dangerous an errant projectile can get, as well to get that power will require more air usage.
It doesn't sound like much power when one compares to a 22rf at 100-130 fpe but 20 fpe is much more power than 8 fpe is!!!
For about 19 years I used 20ish fpe .177 cal pcp's for hunting, a 10.5 grain domed pellet at 935 fps. What I liked is a flat trajectory compared to the airguns I used when I was a kid so range estimation wasn't as critical and it'll drop a jack rabbit DRT or soon after when hit well inside 40Y.
Then I got a 30 fpe 22 cal pcp, a 18gr domed pellet at 910 fps. There's a noticeable difference in impact sound and how game reacts.
Then I got a 25 cal which sent 25gr domed pellets at 900 fps which is 45 fpe. I started using a lot more air and began getting more concerned with somehow causing harm to people or property so I was much more mindful of far away consequences that could result from an errant shot.
Then got a 30 cal using 44gr pellets at 910 fps, about 80 fpe. I treated it like I would a 22rf. Man those pellets smack a critter hard but you use a lot of air too.
Me - If I lived in a neighborhood I'd stay inside 20 fpe.
If I had a little leeway as far as neighbors go I'd use the 30fpe 22 cal.
With both I'd use a good moderator to reduce sound.
The airgun in my pic is 60 fpe and with the brake is louder than a 22rf. The pellet barrel sends 25gr 22 cal pellets at 965 fps. A jack rabbit at 100Y is an easy shot if the wind is normal and plenty of power to DRT.
Pellets blow a huge amount compared to a 22rf at 100Y, this was in fluctuating 8-13 mph winds not using any wind flags but guessing the best I could based off observing grass and mirage. See here in the pic how wide my group was at 100Y using this gun and those pellets which have a .051 G1 BC! Also notice how small the vertical is.
Eh, it gets to the point that using a 22rf just makes a lot more sense in most ways when hunting but there's something fun about experimenting with airguns and not having to worry about a bullet causing problems down range way out there.