That is one of the reasons I hesitate to pay for spotify premium (I only use their free add-based service).
I listen mostly to small bands that don't get much money out of spotify. But still, spotify is great for discovering new and interesting music. I use the Daly Mix feature heavily.
But the real way to support musicians that are important to you is to buy their merch and visit their concerts. That's where my money goes instead of spotify.
I have written a similar Password manager as an UWP for Windows [0]. It didn't get much attention since i never tried to get some.
I could not agree more with the points you mentioned.
To solve the last one I added the option to create an encrypted list for the sites. But so you end with an additional password you need to remember because using the same as for the masterkey makes this the only key to access every password. And this is what the system tries to avoid.
But the real way to support musicians that are important to you is to buy their merch and visit their concerts. That's where my money goes instead of spotify.