Currently, enabling "Mini View" (CTL +1) only allows for this view to be seen and used on the desktop on which "mini view" was enabled. If you have multiple workspaces in use the second you switch to a different workspace "mini view" disappears and you no longer have easy control of the transport button functions without switching workspaces (a necessity to conveniently control and use MC26 in Ubuntu).
IMO, this problem would be resolved by implementing MPRIS2 support, but in the meantime, allowing "mini view" to be visible on ALL workspaces would go a long way to making MC26 more usable and controllable.
Such an option is already implemented with detachable "cover art" where option "CTL +6" permits detaching the cover art of the currently playing track to a separate resizeable window, then right clicking on the header bar of the detached window and selecting "always on visible workspace".
BUG: Unfortunately, this option (detachable cover art window") stops working when switching between "CTL+1" and "CTL +2" and when stopping and restarting playback it looses the setting "always on visible workspace" so that it doesn't appear on all work spaces after restarting playback from a full stop.