Yes you can install again on a different computer. Some of us have done it several times due to the digital version having problems (microsoft sort it out). Just uninstall it first from the old computer to be on the safe side. If you don't know how to uninstall:
go to "add or remove" function and look for microsoft flight simulator 2020 and click uninstall. You can find "add or remove" function easily through the search engine next to the start menu by typing "uninstall".
Enjoy your new computer.