I dont have too many games in my library about 180, but when I go to my library it works so slow. When I click on game icon to open it takes too much time at least 10 seconds sometimes more.
In task manager I saw that gog uses 250 MB RAM too much in my opinion.
At first I disconnected all other platforms epic, steam, origin, ubisoft I thought maybe it will help. It didnt.
It just feel so heavy.
I have good internet fiber optic 300/80 mbs so its not me, I have 16 GB or RAM and 6 core AMD CPU.
Any download works more then fine max speed, I can play any game normally so my only probllem is with library.
Do you guys have similiar experience? I dont know what else to do to make it work better.

Try disabling Cloud Saves under Settings - Game Features and see if that makes a difference.

If not, try starting over with a fresh database and see if that helps:
1. Exit GOG Galaxy.
2. In the File Explorer address bar, go to C:\ProgramData\GOG.com\Galaxy
3. Move the storage folder to the desktop.
4. In GOG Galaxy, click the cogwheel in the top left, then choose Add Games & Friends - Scan Folder for GOG Games to import games you have installed.