You dont need to uninstall and reinstall the entire program, only the 1040 Module.

Windows Add/Remove Programs    scroll down toPS 2021 and click Uninstall, it may come up with a warning about uninstalling the program, thats fine, youre not uninstalling the whole thing, it will open a window with choices like 1040, 1065, 1041  etc, choose 1040 and click Uninstall.

Now reboot the computer and when you come back, open PS and go to Updates > Select and Download New Products and check the 1040 box again, let it download.install.