Genshin, right? Might be an issue on their end, maybe the app isn't optimized for One UI 5 devices.
You can let them know about the issue here: HoYoLAB - Official Community
Oops, assumed from the blue menu that it was Genshin! Lol
MLBB has a report feature baked into the app.
To enter the menu you can go and click Customer Service at the top of your Mobile Legends right screen.
You will find a headset logo on the screen, and please enter the menu. So later there will be many menus that you can find.
Thanks for reaching out to us in order to find out the reason why the ultra refresh rate went missing while playing MLBB on your beloved Samsung Galaxy device.
And we hope that we were able to satisfy your inquiry here.
For more assistance and guidance, you may contact us via our online Samsung Customer Care support channels below.