Is $35,000 to renovate the entire pool (tile, coping, plaster) a fair price?

I've owned the pool/house for about a year, and this is my first pool. Last year, I noticed a narrow horizontal crack around parts of the spa, above the waterline, which might explain a suspected leak from a previous inspection. This year, after extended travel, I discovered the issue, assuming it's from water getting behind the tile and freezing over winter, despite the pool being professionally closed. I've cleaned up some sand and broken tiles, but more sand is spilling out. The pool is from 2000, and the plaster and coping are tired, but I hoped to get a few more years out of them. I'm concerned about risking further damage, especially to the bond beam, if I don't address this soon. I'm wondering if a localized repair is possible or if I need to commit to a full renovation, which I estimate to be around $35k. I also personally redid all the mastic last season, so I'm sad to think it might be ripped out. I'm also curious if it's common for the mortar bed to break down over 25 years and if not addressing it now will lead to higher costs later.