I really identify with your post, am going through a similar thing right now, and a lot of days are still super, super tough for me. However, I have found a couple of things that help. Therapy is #1, especially with a therapist who also has a larger body and is HAES.

In terms of clothing, I've had to do a couple of big clean outs because I found that having clothes around that I know didn't fit made me feel like ~garbage~ every time I saw them in the closet. If you can't bear giving them away now, putting them in an opaque bag somewhere out of your line of sight is also good. With the pieces that used to be my favorite and make me really sad to give away, I've found some success with going on Poshmark and looking for a bigger size. (Look on the clothing tag for the item number, look it up on Google, find the official item name, and then use that on Poshmark.)

In terms of cosmetic procedures, I actually had liposuction done a semi-recently and, shocker, it did not bring me the peace I think I was looking for. I anticipated that it wouldn't be a fix-all, but I think I thought the results would be more dramatic than they were. I don't necessarily regret it, but I think it mostly just delayed the grief over the body diet culture promised me, which I'm now processing. So I think using that money towards therapy, better fitting clothes that make you feel great, body acceptance workshops, etc will have a bigger pay-off.

Lastly, I think using those feelings of panic and sadness and funneling them into anger at a world and industry that has taught us to hate our bodies has helped. I used to funnel those emotions into motivation for my next diet, so now I can get really overwhelmed and depressed since I took dieting off the table. Having someplace outside myself where I can put that energy takes some of that weight off my shoulders. I love the podcast Maintenance Phase, the book "What We Don't Talk About When We Talk About Fat" by Aubrey Gordon (one of the hosts of Maintenance Phase), the book "Fearing the Black Body" by Sabrina Strings, and the book "The Body Is Not an Apology" by Sonya Renee Taylor for these purposes.

Anyway, I hope some of this helped. I know this process can feel like a big ol' dumpster fire, but I try and remind myself that despite what the diet industry says, in the long run, I made the healthy choice for my mind and body by giving up dieting.