Starliner is currently cleared to return. The astronauts are not stranded. Mission leadership has opted to extend the stay on the station because it is the best place to troubleshoot the issues they are having.
Are the Russian Soyuz still being used as ISS-taxis?
The best option I heard in the previous post on this topic was to bump two astronauts off of SpaceX's Crew-9 in August. Then Suni and Butch would stay up another 180 days and come down with Crew-9.