different types of rows (taskbar, systemtray)?
For days/weeks/months I switched from KDE to XFCE until found myself staying up later (had to switch back for night colour control in KDE then was slow/halting again) but switched back to XFCE and am working on configuring/bugreporting redshift-gtk (coming along nicely) but miss several less important KDE features such as their panel has separate numbers of taskbar & systemtray rows.
I don't know how common 4K, 5K, 8K (rather than older/slower hardware with smaller monitors) is XFCE but I still use 4K with double-height XFCE panel but then two taskbar rows put almost all non-minimized program taskbar entries at top left (panel there classic Apple-style) less-reachable/-readable but having only one row extends dozens systemtray icons too far left... so taskbar & systemtray should be able to have separate numbers of rows... and I noticed a few programs minimize to entire vertical space middle of two rows in systemtray while others minimize to a row (all should be forced to).
I noticed even with one row, 11 taskbar items only extend maybe 2/3 across so the bigger issue is I need to increase font size from 10 to 14 (changing in XFCE settings didn't immediately apply to taskbar but I'll restart) nevertheless separate numbers of taskbar & system tray rows is a wishlist/enhancement issue.