Well, it depends. Some tools I want to be OS-consistent and unobtrusive. I don't care for the newish trend of everything having its own 'dark mode' (none of which match each other) or the way this is offered as some great innovation when it's only about few pages of code to implement. I would much prefer to have better theming options at the system/WM level.
On the other hand, I have many specialized tools where the UI is superior that of the OS and if anything I would like everything else to look more like those. Ableton Live was an early pioneer of the kind of flat minimalism that people associate most often with Material Design, for example. At the time it was launched most music software manufacturers were still obsessed with skeuomorphism, albeit for entirely justifiable reasons because musicians often fetishize and want to emulate the sound of particular pieces of studio equipment.
On the other hand, I have many specialized tools where the UI is superior that of the OS and if anything I would like everything else to look more like those. Ableton Live was an early pioneer of the kind of flat minimalism that people associate most often with Material Design, for example. At the time it was launched most music software manufacturers were still obsessed with skeuomorphism, albeit for entirely justifiable reasons because musicians often fetishize and want to emulate the sound of particular pieces of studio equipment.