Don't overthink this too much. 7-Zip beta works flawlessly on Windows 10 64bit for me. The difference between stable and beta version is negligible and only exists in features you'll likely never use. So it doesn't matter in the slightest which you choose. So go for the latest one - the beta, and all will be good :)
Honestly, just go with the beta. It'll do everything you need it to just fine. Plus, if for any reason at all you're not completely 100% happy, just uninstall it. It'll only take two minutes and won't leave any remnants behind. So just go with the beta and everything'll be fine.