Assuming you are using the fast hardener that's what it gets to, properly mixed right ratio etc. Other hardeners are lower. Anyway, look at the heat defletion temperature values. You might find them interesting.
https://www.westsystem.com/products/compare-epoxy-physical-properties/
Now if you want the ability to warm it up with a hair dryer, apply steady pressure, and slowly bend your fins back into alignment, go for it! I've used that method for fixing warps in parts made with West.
Just because you can usually get away with using something, doesn't mean it is really a good choice for the job. I wouldn't use it for surface mounted fins for instance on MD rockets. IF you are through-mounted, then the fin stability is much greater and likely you would never notice any issues. But I'd stay under M2.
I have experience with a variety of epoxy systems, some suitable for aerospace and some not. West is a great epoxy for working on wooden boats. And I've used it a lot, probably gallons by now, even for things like ebay sled glassing. It is available and convenient, but I recommend using something more suited to the job if it is going to get exposed to heat. That's just basic engineering.
Often you can use an inferior material if more of it is thrown at the problem or if it only has to work once.
Do what you want of course! I didn't mean to step on anyone's toes. But we have a lot of beginners here who will never have heard of Tg and don't know that various epoxy systems have different properties to suit their intended purposes.
Gerald