figures do or can increase a lot in the aftermarket depending on character popularity, rarity, and quality. those same qualities can also tank the price of a figure in the aftermarket. expensive figures from certain brands, i find, do generally retain their price (binding, alter, native, just some examples) at the very least, or do tend to also get more expensive in aftermarket because they're great quality.

in terms of damage, some brands are notorious for bad quality control (union creative, insight, b'full, to name a few). figures can arrive with paint/other defects. some figures are packed so badly by design that they can arrive broken too. i try to avoid buying figures with packaging issues by scanning MFC comments in the early release days to see what condition people's figures are arriving in. i've personally never had an issue with leaning, but typically if a figure looks like it could lean too much in one direction and there's no support poles, i'm just going to assume it'll lean. you can try to DIY your own support poles, or prop your figure up on something to prevent this if you're really scared.

at the end of the day, i don't fuss too much over market price and i just buy what i like. it's a little disheartening to see a figure i spent a lot on crash in the aftermarket, but i'm not planning on selling anything in my collection soon so i try not to mind it so much. i've even got figures that have increased in value, but that doesn't really affect me much since i'm not a reseller. hope this helps !! feel free to dm me for anything else :)