If you can see a snake in time to pull and shoot, you had plenty of time and space to get away. Plus…shooting wildlife seems counter productive to nature observing?
Stray dogs, bear spray is going to be much more in your favor. Gel so it doesn’t blow back in your face.
Rabies is very uncommon in the US, your area may be different but most areas this is not a concern. And remember, Hollywood Rabies is not like how it often presents. Yes, the foaming aggressive animal can occur, but you’re far more likely to encounter a stumbling around like it’s had a stroke with some drool animal. But, lethargic stumbling over itself, totally out of it look, doesn’t sell in theatres. The “mad rabies” can and does occur, but a very tiny percentage of actual rabies cases. Bearspray here too. Or just, like, walk away. (Also: consider this a PSA to anyone rescuing that seemingly in trouble animal stumbling around awkwardly or moving/behaving in “off” ways - be aware that may well be rabies, take caution).
A weirdo guy following you, bear spray will work there too.
TLDR: bearspray. Far safer for you to carry, will do the trick in practically every case, and probably a lot easier to acquire than a gun.
The thread Lifechanging Upgrades has a lot of “what do you carry”.
https://forum.inaturalist.org/t/lifechanging-upgrades/32893/69 is my reply that has some things less thought of that I carry.