Hello, and thank you for your question!
Currently, the way to restore a previous version of a proposal is to Create a New Proposal through the proposal history, as you describe. If you want to only keep the restored version, you can right click the proposal you browsed the history of and Delete it.
More information here: https://help.autodeskforma.com/en/articles/8520133-go-back-in-the-history-of-your-proposal-with-the-...
If there are any issues with this approach, we're very open for feedback for how things can be improved! 🙂
Kjetil Bugge KristoffersenPrincipal Software Engineer