THIS sack of shit extension was the culprit. Gone and back to 25 in Vivaldi with all other extensions active. Acceptable. https://chromewebstore.google.com/detail/blacker-text/nmmmdgooonmibfppcponjkaoohgcdpbd
Edit: #uBlockOrigin was slowing things down as well, gone. Will stick to the built-in blockers in #Vivaldi.