I pulled the latest Cutefish Videoplayer file from github and there are no titlebar buttons. No close, maximize, or minimize buttons.
I also tried to hove over on each corner but there were no options appeared.
[My System Configuration]
OS: CutefishOS (Ubuntu 21.04)
Device: Virtualbox 1.2
Processor: Intel i5-8250u (4 thread assigned)
RAM: 4 GB