hmm, kk, that seemed to work. Thanks for figuring this out!
now, I've hot to figure out on which vivaldi.exe property to affix "--force-renderer-accessibility" too so that it always launches this way as its my default browser.
I've had trouble with other apps getting through to vivaldi as well, such as Flow Launcher,
https://www.flowlauncher.com, has several plugins to read bookmarks, send urls and website searches, etc, to your web browser.
I've recently made a post in their forums about this browser being problem (despite it great ui features), and only got a copy & paste answer that wasn't helpful.