Update: Reverting back to 4.145.0 solved this issue.

The most recent version of Lastpass with passkeys has broken TouchID on MacOS. Lastpass trying to save passkeys results in an immediate "Unable to authenticate it looks like you canceled the passkey authentication process", because it is interfering with the MacOS touchID passkey process. Thus it is unusable on websites that I use TouchID on, and also locks up the browser, forcing me to force quit and restart it. Please issue a new update.