I run Brave on Ubuntu Noble where it is installed via snap. I have the latest version 1.75.180 Chromium: 133.0.6943.126 (Official Build) (64-bit) as of today.
Startup times are horrenduous since the beginning of the week (shortly after the change was made to allow tab groups in the bookmarks bar). We are talking about 1 hour running at 100% on a single core.
My extensions have not changed since last week. Let me know what other information I can provide to zoom in on this.