One of the first things I do before I even post in a forum, is to either customize the default avatars, and/or upload my own, even when I got my first PC, (or any PC for that matter) I spent the entire day customizing everything, as I always detest the default settings of any program, so looking at this forum, I don't expect there to be nothing in the way of personal customization...
So the main reason I first started using Opera (Around 2002 I believe) was that Opera shared my own total contempt for the default settings, so like everything else that is computer programs, it's been marred by the overwhelming blandness of the off-white realm of the office manager/cubicle commoners! :^) JK
I would keep Vivaldi in mind as a possible viable main browser to, or even along with "Neo-Chromium" as they're much more dedicated to the enthusiast, and Original and long supporters of Opera. I still use it in the hopes that someone, -any-one finally comes up with way to change the horrid skin color!
I personally still use "Opera" along with every other browser, (save for Safari/IE, and only 10% of Chrome) so I would just give up any personal customization here,(Else it would've been enabled already) and suffer through the off-white blandness of forums/Programs safe for the office...
'Cause Casuals, gonna Casual...