HOA is ruining my life

Hello,

I recently purchased a ground level flat above a garage door. Im my initial visits the garage seemed pretty quiet, a few cars came out and It didn't really feel like a big deal. Nowadays its ludicrously loud (especially the door) and I've learnt my living room is not well insulated and there's really no space for insulation down there. I've had an engineer come over and measure sound and it's well above legal limits, but the HOA refuses to change the door because it's "too expensive"

I don't have the money to sell right now, and I have rented one room so I cannot evict the tenant. I don't have anywhere else to go, I'm taking mood stabilisers and anxiety pills to try to combat this but I feel horrible.

I feel like I'm being kicked out of my own home by negligent neighbours, I am devastated.