The Stealka malware is inserted into pirated mods for video games including Roblox, and can lift sensitive info from apps.
The easiest way to do it is to right-click the app's icon on the Dock, then click the "Quit" button. The Santa hat should be gone now. If it isn't, check whether the "Allow automatic icon changes" ...
Deleting the WinSxS folder is unsafe. Learn what WinSxS does and how to clean it safely using Disk Cleanup, Storage Sense, and DISM to free real space in Windows 10 and 11.