how many versions of .net do I need on my laptop

I have what I thought was a simple question, but cannot find an answer anywhere.

On my windows 10 laptop I have 2 versions of .net: (info from Revo uninstaller)

- Microsoft .NET Runtime - 5.0.17 (x64), 91.09 MB 5.0.17.31213 32-bit

- Microsoft .NET Runtime - 6.0.25 (x64), 95.63 MB 6.0.25.33019 32-bit

[1] Do I need them both, or can I uninstall v5 and then v6 would be backwards compatible?

[2] Likewise if I need a later version of .net, could I uninstall earlier versions.

My apologies as a user rather than a programer