Hello there! I'm glad to help you today!
Since you have already cleared cache, please reset Microsoft Gaming services.
Press Windows Key + X
Click Windows Terminal (Admin)
Copy-paste this exactly, then press Enter:
get-appxpackage Microsoft.GamingServices | remove-AppxPackage -allusers
Wait for it to finish, then please paste this next:
start ms-windows-store://pdp/?productid=9MWPM2CQNLHN
Your Store will open.
Click Install on Gaming Services
Restart your PC
After reboot, try installing Roblox again.
Also, let's also check for corrupted system files.
Click Start, then type cmd.
Right-click on "Command Prompt" and select "Run as administrator".
In the Command Prompt window, type:
sfc /scannow
Press Enter.
Wait for the scan to complete. It may take several minutes.
Follow any instructions shown after the scan finishes.
Next, open Command Prompt as an administrator again. In the Command Prompt window, type DISM /Online /Cleanup-Image /RestoreHealth and press Enter.