Star Trek canon does place the Riker bloodline as far back as the American Civil War, so it’s possible that an ancestor could’ve found their way on Starfleet between now and then.
But perhaps Jonathan Frakes could take on the role of another character in the Star Trek universe, just so fans can have a chance to see him on a starship again.
It’s worth mentioning that Frakes has appeared in every Star Trek show he’s directed, so it would be a terrible streak to break if he stopped now.
Having a Riker ancestor briefly on the starship would be neat considering the show has gone to lengths to bring back characters from the original series.