Battery life

That's not a question for developers forum. You'd better post on Apple support community: https://discussions.apple.com/welcome

And remember, that's a beta, so not necessarily optimised. Wait for the official release to check if the problem still there.

As @Claude31 says, the beta releases are not optimised. They contain extra processes that run in the background collecting data and performing extra logging so that Apple can tweak the software before release. This undoubtedly uses extra battery power.

You shouldn't install the betas on your primary device. If you have a spare device - your previous iPhone, for example - try the beta on that, and only install the finalised general release on your main, primary devices.