You do not need to pay $70 upfront. Microsoft Flight Simulator (2020) is included in the and Xbox Game Pass Ultimate . For a subscription fee (often as low as $10-$15 USD per month), you can play the full Standard version instantly. This includes the 40th Anniversary Edition updates.
Creating content around a file like Microsoft Flight Simulator V1.37.19.0.rar suggests you're looking to share or explain a specific version—likely a recent —of the simulator. Microsoft Flight Simulator V1.37.19.0.rar
Safety & Legality (critical)