I use Citrix Workspace for the Mac daily on my MacBook Air (M1). Works fine on the M1 -- it does use Rosetta 2, but you'd never know.
If you're downloading a .ica file from your workplace as a link to a Citrix-based application, know that Safari will not automatically open the file. You must open your downloads folder and manually double click on the .ica file to open it in Citrix and begin the session.
Chrome, Edge and (I believe) Firefox can be set to automatically open/launch the file.
Otherwise, Citrix Workspace works fine on the M1 Mac with no special configuration as compared to Intel-based Macs.