I meant the last one of those. If you have a directory of lose files, you can just open any of them and compare them directly, but if they’re all in git, you’ll either have to make a copy of your current version before checking out the other one (because it would be overwritten otherwise), or like you said, use multiple worktrees, which is a rather advanced feature (that I honestly didn’t even know existed until now).

Either way it’s a bunch of extra work and it’s only necessary because you chose the wrong tool for the job.