I just upgraded to Nextcloud server version 30. And I really like the new, slim UI elements in the web UI on the desktop browser.
It saves a lot of space. This also helps working on the big 20"-30" desktop monitors. But it especially improves the experience for medium sized 14"-17" monitors on notebooks. For me this represents a professional design which greatly supports professional users.
Please keep going and maybe save even a little more space on the big screen. The more information I can see at once without scrolling, the better I can work.