So, I want to do some martial arts, for self defense. Ideally one that will be useful without giving me CTE, or any long term bad stuff, even though I feel this is already asking for too much 
I don't live in the U๐๐ so gun related stuff isn't really an option.
I'm somewhat heavy, with a year of experience in lifting, and my cardio is not the best, but I can do long walks (of 1 or 2 hours) before getting tired.
I'm going to move to a bigger city in September, and there's a lot of stuff available, so you can comment on the more niche options.
So yeah, any advice from your experiences is welcome lol
If I had known people started arguing over my post I wouldn't have made it.
What ever has a cheap gym near you where people are nice.
Your milage may vary. Boxing is useually good but in lots of places people play too rough. MMA is cool but could be over priced or the gym could be full of right wing types. Kung fu is fun but it is entirely too dependent on local situations to guess. Around me kung fu places were elementary overpriced day cares with dubious predatory self help stuff attached.
Oh every gym in my area is full of right wing types