I get, and approve of, ending your sponsorship via ads. But I don't think legal recourse should be rewarded.
Any business transaction has risk. If you decide to advertise on Superbowl, you're putting your chips on NFL.
If you're advertising on Twitter, after the Musk purchase, your money is on Musk and Twitters staff to continue the value. If Musk says stupid shit that devalues your investment... well, that's on you for putting your money on it, and not exercising your exit clause a year ago.