Some thoughts on your list from my side:

2) Signal - can be registered to anon sim a later you don't have to use it, it's just first reg. I think they use twillio. It is workable.

Another option is Sessions app. No number required. Only downside is network effect.

3)There's AppFlowy. You can run it locally. Problem is that UI is not good.

5) Passwords: What about to use something like open source password manager + TOTP 2FA on second device? You don't rely only on Master password.

7) Number: Try keepgo.com or silent.link . Hushed is ok, but sometimes it might not work. Those sms4sats work pretty good for sms verifications.

8) Phone: Banana phone with wallace toolbox can change IMEI and with anon SIM it is a solution.

9) That is true, works for some time and than it discontinued. Unfortunately that is the truth.

10) Paying cash and smaller accommodation solve this problem. Or to have another ID card. (more various residencies)

11) That is pain and cancer, agree. But simplelogin is solving it.