I waffle back and forth between a revolver in 44 Magnum and a semiauto in 45 ACP. However, a 460 Rowland kit gives me medium level 44 Magnum on a semi-auto.
Another problem I have is gunsmithing and parts replacement. The only gun I can work on with confidence is Glock. I can do all work except fit a barrel or fix the slide. A 460 Rowland kit drops in, as does a 22 Conversion. All parts are available, assuming the frame and slide do not break. In that case, a Glock 21 makes a whole lot of sense for me. I would buy two spare KKM barrels, a spare Glock 21 barrel, all the frame and slide parts, and a whole bunch of Glock gun and magazine spring sets. 100 magazines ought to be enough. I would buy additional 10 round mags for the 460 Rowland since the springs are heavier and tweak them as needed. The G21 with 460 Rowland conversion would require a different holster since it adds an inch or so.
I really like the SIG P220 SAO and DA/SA. It too can be converted to 460 Rowland, but I am not certain about how good the SIG 22 Conversion kit is. It's another possibility, but I cannot work on them at this point and would attend SIG armorer's school.
A S&W Model 29 round butt with 4" barrel would be my choice of revolvers. Just add gold bead sights, slick up the action, and do a few other things and it's good to go. I would attend gunsmithing school to learn how to work on it. I certainly would buy a bunch of parts, including spare barrels, a cylinder or two and so forth. 44 Special would be my primary defensive load but I'd have lots of 44 Magnum ammo available. I do prefer Federal 44A SJSP at 1250 FPS. Unfortunately, there is no possibility of shooting 22 LR from a Model 29.
Another possibility it to go with a Glock 17 (or 19 or 45). The 17 is known to be good for several hundred thousand rounds (see Chuck Taylor's article on the topic:
https://www.ballisticmag.com/2018/05/23/glock-17-torture-test-ocean/). The downside is that 9mm isn't a good hiking caliber, but Rowland offers their 960 Conversion that may yield some decent 357 Magnum performance out of it. But, I am not so sure about that caliber. 9x19mm is probably good enough for 99% of my requirements anyway.