I had the same issue, following a Windows upgrade earlier in the week Brave kept crashing after a few minutes or less, without writing any crash report. After fruitless attempts to disable gpu, disable all extensions, uninstall and re-install Brave, I uninstalled Brave, cleared out all data in Program Files(x86)/Bravesoftware and C:\Users<Username>\AppData\Local\BraveSoftware , restarted, reinstalled Brave, re-enabled sync w my mobile, imported the old extensions from Chrome. I also unchecked enable hardware acceleration(whether needed or not). Now Brave has been running for a couple of hours without crashing. Hopefully it stays that way…
— Update — 30 mins after writing the above I had a banner show up saying a new version 2 of sync is coming. Click here to learn more. I made the mistake of clicking on it, which immediately crashed Brave. And now its back to crashing every 30 seconds or so (5 times just when writing this text) … No crash reports are written.
Unfortunately it seems Brave browser and sync have a long way to go in the stability area to become a contender to replace Chrome.