Currently, I'm struggling to maintain a TA reading of 80. My pool is almost a year old, but the SWCG came online about 2 months after the pool was built.

My scenario goes like this...pH 7.5, TA 60. Add baking soda to raise TA. Then pH goes to not-quite 7.8, TA 70. Add more baking soda to get TA to 80 but now pH is a solid 7.8 or 7.8-plus. Add muriatic acid to reduce pH to 7.5 and then TA falls to 60 again. This cycle happens once or twice a week, so I'd be very happy to have your schedule of adding acid every 2-3 weeks. I do have a waterfall which "helps" to lower my TA on a regular basis.

I'm not a candidate for borates due to having a dog drinking a fair amount of pool water.

Whether at 60 or 80, my pool still looks nice and clear. But, like you, I wonder how low my TA could go and still be OK.