I need a 360 proof rim v. mountain bike

So I just put new derailleurs and brakes on this old raleigh m30 I found in the garage. its pretty decent.

I can do 360’s flat on my bmx bike but cant barely bunny hop on the mtb. I tried a little spin and put a decent bend in the rear rim. I bent it back but this is not going to work well long term.

I’ve always had double wall alex’s on the haro but idk what I’m looking for in regards to mtb’s. I’m not looking for anything new or top of the line. old and heavy is fine as long as I wont bend it.

You can have the best rims in the world, but if you have shitty or loose spokes they will still bend to shit.

Yea true, but the spokes are tight on this rim. its just a chintzy set up really.