Hello,
Those restrictions are set by policy. If you have not changed any of them and have not installed any third-party "system optimization" software, it is possible that the system is pre-configured to not let you install the language packs.
Do you use a third-party tool or third-party ISO file to install Windows? If so, those policies could be set in the installation media.
Based on your situation, since language packs and the policies can be applied per user, you can try using a new user profile by creating a new local administrator account.
To do so, right-click Start->Terminal/PowerShell/Command Prompt (Admin), then type the following commands:
net user /add user1 pass1
net localgroup administrators user1 /add
(Replace "user1" and "pass1" to the username and password of your new user.)
After creating, press Windows+L to return to the log-in screen, then select the new user in the bottom-left corner and log in. Check whether the new user still have this issue.
Please note that if the new user also has this issue, you need to reinstall your system, so please back up all your personal data to offline storage (like USB sticks, external HDDs, and memory cards) beforehand to prevent data loss.