Personally I will delete the folder manually after you close Steam.
steamapps\common\Age of Empires IV\ - delete whole folder than delete C:\Users\your user name\Documents\My Games\Age of Empires IV - whole folder again.
Reopen Steam verify files of AoE4 - it will redownload whole game. Hopefully will fix the folder permissions issue.
A friend of mine is having this issue as well. He is using Windows 11, we’ve tried reinstalling the game, and even reinstalling Windows, and the error persists.