my advice is not universally applicable, sorry. i had a very strong mysore style ashtanga† practice in my 20s, that i at some point abandoned. i simply picked it up again, and it still took me close to a year to get my spine dynamic enough, get my muscules moving to arest and maybe revert some of the ossification? it's not visibly there at this point, but through close athletic observation i know it's not ever going to be 100%. i've complemented it with an occasional chiropractic adjustment and massage, but that's about it. i didn't start it exclusively for the purposes of fixing the hump, i realized that i'm getting old (in my 40s now) and that i will greatly regret slowly degrading into old age without having the experience of fit working body again.
†https://en.wikipedia.org/wiki/Mysore_style https://en.wikipedia.org/wiki/Ashtanga_vinyasa_yoga https://www.youtube.com/watch?v=aUgtMaAZzW0