I would rather be the main actor in a really bad movie.
If I’m the main actor, I am not only going to be paid well for my work, but in terms of career progression I am going to be the most visible to prospective casting agents and producers. Plenty of actors started out in utterly awful movies, but used them as a means to leapfrog into progressively better projects. Take for instance, this star of the utterly terrible movie Hercules in New York.
Schwarzenegger starred in this film aged just 22. It’s not as if Schwarzenegger wowed people with his incredible acting talents, but the role was prominent enough to bring him to the attention of future casting agents who needed a big strong looking palooka in their upcoming projects. Do people remember him for Hercules? No, they remember him for decades of successful roles in better movies.
I’m not saying that you can’t work your way up from smaller roles into better ones, that’s how most actors do it in Hollywood, but most would kill for a chance to star in any movie, and most aren’t ever in a position to accurately judge if the movie is going to be objectively terrible anyway.
Basically all the lead actors in Star Wars thought it was a trash movie. Carrie Fisher thought the movie was stupid, Mark Hamill hated his own acting, Harrison Ford utterly hated being in them and wanted to be killed off as soon as it was narratively convenient, and Alec Guinness kept telling his fans not to watch it.
Were they right though? No, they all did very well out of it, and produced the single most successful and beloved franchise of all time.