Good question in fact and I just did some research on Google and Stake has a multi-year sponsorship with Watford. It will be a huge blow if Watford would already relegate after they just promoted to Premier League, but maybe Stake can give up the sponsorship if they relegate...
https://www.watfordfc.com/news/club/official-watford-fc-stakecom-announce-new-multi-year-principal-partnership#:~:text=Watford%20today%20announced%20a%20new,return%20to%20the%20Premier%20League.
It's not hard to find a new team to sponsor it depends on the budget provided by stake.com they can find a top team or vice versa
If I was appointed to look for a new team of choice I would go to Newcastle this team is predicted to do a reshuffle next season
Regardless of whether this news is true or not, what is certain is that Newcastle still survives in the Premier League.