Unfortunately, most of us (if not all) are trapped in the same way. The only really private option is to start again. I've already gone down the GrapheneOS, nostr:nprofile1qqsdn44vrgyvte46jcpv9lk7we9zfgrs7jqk04a3kucq345x376dn7spz4mhxue69uhhyetvv9ujumt0wd68ytnsw43qqj42ps route but, as you say, I still have links to my identity. My phone contract for one. When I retire (not too long now I hope) I will buy a new (second hand phone) with cash and go full silent link and start over.