You can provision VPN servers on your computers and give them out to Russian nationals for free.
Why take the fun out of it for them? Between russian based spam on my web contact form and a third of the port sniffing coming from russian based addresses it seems they love a challenge. I'm not giving it to them for free.
I would guess the erliest would be if either Ukraine surrenders or there is a domestic protest that puts Putin under severe pressure. The latter probably only works if Putin has to step down because I don't see him backing out. Otherwise increasing sanctions to disrupt the supply for the war machine is probably most effective. Don't cut communication lines to Russians, try to get information to them that counteracts state propaganda.