The solution is to sync your passwords to your Microsoft account - if using Microsoft Edge - or, alternatively, to your Google account - if using Chrome. Other browsers have similar capacity to save stored passwords to the cloud.
The whole idea of storing passwords in your web browser is the ability to save them to the cloud in order to sync them. Otherwise, not only do your passwords have no backup, you are limited to using your passwords on only one device in the whole world.
It is inevitable that substantial changes will be made to Microsoft Edge by an update. The whole idea of an update is to introduce changes. And sometimes those changes could very well affect stored passwords, and not in a good way. In my case, I use Google Chrome as my browser, which is also the default browser for my Chromebook. Google updates Chrome and the ChromeOS (which powers my Chromebook) even more frequently than Microsoft updates Windows and Microsoft Edge. If my passwords were not stored in the cloud, they would be at risk with every update. But when you store your passwords in your Microsoft (or your Google or iCloud) account, updates are a total non-event, because your passwords will be restored automatically, without you needing to do a thing. That's what syncing is about.
A very popular alternative to storing your passwords in your web browser is to store them in a third-party password manager, like 1Password or LastPass or Dashlane or any of the other password managers. Now you can easily use your passwords on any browser, anywhere, and you don't have to be worried about losing your passwords because they are stored in the cloud and sync automatically.
If you think about it, updates aren't the only way your passwords are at risk. What if your browser crashes, or stops working properly, and you have to re-install it - you could easily lose your passwords that way. But when you sync your passwords to the cloud, you don't have to worry about it, because your passwords are waiting for you.
The solution is not to stop updates; the solution is to learn how things work, so you can make them work for you.