Hi, Windows has a habit of removing from Start Menu anything that competes with it's programs.
From Start Search type the name of the program and double click it to run, Or find the folder where you installed it. (I install all paint and Photo software into 1 folder so know where they are, as paint can be used to edit photos or view them.
From Start Search type Microsoft Store and double click and open it Please , go down the left side to library and install Paint Update and anything else you use.
The Microsoft Store is a Integral Part of Updating Windows 10/11.
If paint program is still slow. Uninstall what ever including Photos by using Powershell Command listed in the URL : https://www.majorgeeks.com/content/page/remove_windows_108_and_8_1_built_in_apps_using_powershell.html This does not remove the MS App but only uninstalls it from where ever and Registry.
then reboot.
then Reinstall Photos with Powershell : https://www.tenforums.com/tutorials/3175-reinstall-re-register-apps-windows-10-a.html then Update from the Store and reboot.
@cryptodan fyi : all Apps listed in the URL's are Updated through the MS Store, especially true for Win11.