I've been researching this thing quite a bit and there are quite a few minor mutations (I think 40+ known?) and the biggest problem besides not knowing if we can really even develop an immunity to it, is that if we do, it might only last for a few weeks or months (at best.)

This is almost in line with things like SARS and MERS, but those are now far less widespread. During flu seasons, a temporary (partial) immunity that only lasts weeks or months is generally sufficient since the seasonal change tends to ratchet-down the spread (of the flu) anyway, so you don't need a long immunity period since the next flu you get is going to be different anyway...

With this stupid virus, we don't have enough data yet on how it weathers (literally) the change in seasons and we also don't know how fast you can be re-infected, especially by a different-enough mutation.

There have been numerous cases already of re-infection already, and also cases where they isolated multiple simultaneous infections of different strains in one patient. That one sucks hard, and you'd also expect a re-infection to be rather seasonal...kind of in line with mutations, like the flu, but this cocksucker virus is mutating like mad and isn't giving a flying fuck about whether or not it's "in-season" either... Influenza mutations take longer to circulate, but SARS-CoV-2 is way worse in many regards.