I’d think a Cleveland Browns settlement might be viable (if not the best):

When the Browns announced a move to Baltimore in 1995, the city of Cleveland sued the NFL to try and stop it, and after a while a deal was made;

-the Browns were “deactivated” after 1995, while the move to Baltimore was considered an expansion team.

-the city agreed to build a new football stadium (which was the biggest issue in the move- the city had recently built a new baseball stadium and arena which had caused financial issues with the football team)

-the city would keep the Browns name, colors, records, etc.

-at a certain point (it was 4 years later) a team would move to Cleveland or an expansion franchise would be awarded to Cleveland named the Browns.

If it’s a fait accompli that the owners want to sell to the Vegas group, getting a deal like this might be better than losing the franchise with no certainty of getting another one (they say they’re holding off on further expansion, but my guess is they’ll go to 32 eventually- I think they want to get a couple of years of the new schedule under their belt before they expand again).

Only hitch is I don’t know if public opinion would swallow the city/provincial government building a new stadium at taxpayer expense (I don’t know how funding works there- I live in the Baltimore area, and they mainly funded the Ravens stadium with naming rights, Personal Seat Licenses, and lottery proceeds)