replacing Adobe flash player on my mac

There is no replacement for Flash. It's dead. Any app or web site you use that still requires it needs to be updated to work without it.

No.

Adobe has as of December 31, 2020 ended full support for Flash.

Webmasters who won't abandon it, need to read the historical remarks on this tip:

https://discussions.apple.com/docs/DOC-250003586