This bug seems to have just been fixed with the rollout of the latest version of Opera.
I was just recording a video of the bug occuring on Opera 111.0.5168.25, but the browser just updated to version 111.0.5168.43. Now i can no longer reconstruct the bug. The tabs seem to respond way faster now, too, and drag & drop of tabs doesn't cause the browser to stutter any longer.
My method of reconstructing the error in 111.0.5168.25 was:
Open a new instance of Opera (e.g. private surfing mode).
Open a few Opera tabs with different sites, just so they load content from other websites.
Open new, empty tabs and move them in the bar, until the crash occures.