Tab navigation not working in Vivaldi

My Read-Only Link

I want to make my portfolio more accessible. One way of doing this is to add keyboard navigation for interactive parts of the site (ex. links). When I followed the guide on Outlines from Webflow University I made sure to add the Focused (Keyboard) state to the nav menu, portfolio pieces, and lightboxes on my portfolio. When I use tab navigation in Edge, Chrome, and Firefox the outlines show as intended. Yet when I tried the same in Vivaldi (a Chromium based browser) the outlines would not appear. I am not sure why this is happening and it’s unfortunate to see. I’m wondering if this would happen in Safari as well but I do not have access to a Mac to try it out. What can I do to ensure the outlines work in Vivaldi as well?

Browser versions I tried:
Firefox 103.0.2 (64-bit)
Chrome 104.0.5112.81 (Official Build) (64-bit)
Edge 104.0.1293.54 (Official build) (64-bit)
Vivaldi 5.3.2679.70 (Stable channel) → Only browser the outlines won’t appear in