I found another thread here with a similar issue: https://github.com/ublue-os/bazzite/issues/1016

There’s a comment at the bottom from noelmiller that says:

This issue has been plaguing us since the creation of the ISOs. We are aware of this issue and are actively working on a replacement effort for the existing install process. This is unfortunately an upstream issue with Anaconda and until we have a replacement ready, there is not a lot we can do.

Other posters in the thread have said sometimes they got it to work just by trying the process repeatedly. Problem probably isn’t you; seems like the installer just isn’t very good…

I assume you’ve probably already seen these pages – but in case not, and also for my own future reference, here are the installation and install troubleshooting pages:

• https://docs.bazzite.gg/General/Installation_Guide/Installing_Bazzite_for_Steam_Deck/
• https://docs.bazzite.gg/General/Installation_Guide/troubleshoot_guide/

The 2nd link there has a video of someone switching into terminal mode to work around a similar generic error with the installer.