If you are looking at dropping quarry then a multishot is way better than a single shot PCP which is way better than a break barrel or under lever springer/gas ram.

Side lever is also better than bolt action imho depending on make/model

There is NOTHING wrong with the AA magazine system. Very reliable.
The issue with AA mags is they are prince Charles sticky out so saddle clash and some scopes will not be happy. Plus being enclosed and full of spings, then crud build up can be a factor.

The best multi shot mag system is still the HW100 system Inc. the single shot adapter.

Air arms regs... hmmm.... I am not convinced they have really nailed it tbh.

Their knock open valves are fine... but you need to know your sweet spot. You do your part and the valve will do its part.

A reg is better in terms of flat lining consistency imho (when they work) but the knock open will serve you well.....