alt Hacker News> stable, but customizable UI,
Which you can't get without modernization because pre-modern solutions don't offer that. But also, what do you do throughout your "entire life" if you want to customize something to do what's not implemented? That's also modernization.
Effectively all you're asking for is a simple opt in so you can change at your own pace
> Which you can't get without modernization
What kind of "modernisation" do you think is necessary for that? XFCE like 12 years ago was already pretty customizable and it remains customizable. Themes, colors, button layouts, some behavior and effects can be changed. XFCE panel allows full customization - I can choose its position, start button logo and text, shortcuts and other elements. It's as flexible as it can be.