Bitwarden on Amazon Lightsail server. It costs $3.50/mo to self-host which is very competitive comparing to paid password managers.
I use bitwarden_rs[0] server written in Rust which is much lighter implementation you can run on cheapest 512mb instance. Official bitwarden[1] server is using docker and mssql which requires a lot of RAM.
You can run it on Linux through Firefox extension as well as on any operating system, including iOS and Android (native app). iOS and Android apps have system Password Manager integration which allows you to skip running app manually in most cases.