I received and used my 3 year visa last year. I seem to remember reading on this site that invitation is only needed when applying for the visa, and after that you just use the visa. But I can't locate the info so I guess I need to make sure.
There's also a link to a covid-related document on Rospotrebnadzor's site, but I can't connect to any part of the site
Your site was invaluable in getting me there last year, thanks