M51 users report these bugs.

[IcyJay30]

If you facing these bugs then send feedback

A- 2 Same notification when manually updating weather from homescreen widget.

B- Video recordings save in HEVC format. But It always show MP4 in default gallery this issue is since beginning.

C- HDR is not upto mark if face and a light source(tubelight,sun) are in same frame specially from front cam.

D- Game performance have downgraded since OneUI 3 update specially games based on OpenGL.

E- Few deep sleeping apps are sending notification(means somehow they are able to run in background).

also when you add any app in deep sleep same app is also addable to normal sleep. Which Wasn't the case earlier. 

Test things above by yourself then report.

Cleaning cache/data, safemode, wipe cache partition, reset isnot the solution!

[KaushalS]

But actually Codm has its own problems like bugs and all so I can't blame the update of Android like if you see it was also the same problem in my old device Motorola G5s Plus so ... Codm is actually a laggy game

[IcyJay30]

Codm or any high end 3D game will obviously lag on snapdragon 625.
For me performance was degraded after update.
https://r2.community.samsung.com/t5/Galaxy-M/Facing-Frame-Drops-While-Playing-Game-on-My-Samsung-M51...

https://r2.community.samsung.com/t5/Galaxy-M/Heavy-lagging-issues-while-gaming-in-Android-11-update/...
And bug is something which doesn't every user.

[GalaxyF23_5g_user]

The latest update has solved the HDR issue.

[IcyJay30]

Try having face and tubelight in same picture.
Mostly its solved but not this scenario.

[Samsung_Support1]

Dear Samsung Member,

Greetings from Samsung Customer Support!

Please register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).

Thank you for writing to Samsung.

Warm Regards,
Samsung Customer Support