@grgnd thank you for the support. Adguard filter support would indeed not only improve the built-in adblocker, but also make more people migrate from adblocking extensions. A win-win for Opera and the users imo.
One vertical scrollbar may be a somewhat different request anyway ... in old (Presto-based) Opera there were two different options referred to as Tiled and Linked, Tiled allowed several pages to be viewed at the same time, but each pane was separate and could be scrolled or navigated independently. Linked was specifically for side-by-side comparisons and scrolled both panes together. You're asking for something more like Linked tabs - some people just want to more efficiently use space on large monitors by showing multiple (potentially unrelated) pages at the same time.