> Last time I tried Vivaldi (over a year ago), the browser shortcuts were taking precedence over website shortcuts. I noticed this in Google Sheets and others. I hope that's fixed now

I feel that's how it should be.

OS > Browser > Browser Extension > Website

Using some sites(JIRA in particular) in Firefox is painful as they just capture every keypress/combo regardless of whether they need it or not. Yes, it's lazy on the website devs part but that is why I think they should be last in line.