I installed it recently with the only problem being the stupid not apparent setup after its installed. They made it kind of crappy lol.
Since you are confused, if you can get it installed, just do it from the UI in optional features. It should install from there or your Windows install is not in good shape which is a different issue.
If it is showing installed in optional features then you just haven't done the setup part. Also can try a reboot.
Everything you should need is here:
https://virtualizationreview.com/articles/2020/05/21/ssh-server-on-windows-10.aspx https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_install_firstuse
With the error above, this might help correct your Windows install without a nuke (read everything first including all comments):