Hello, thank you for reaching out to Microsoft Q&A.
The minimum system requirements vary depending on the version of Microsoft Flight Simulator you want to play.
For example, if you are playing the latest version - Microsoft Flight Simulator 2024, there are three levels of system specifications: minimum, recommended, and ideal.
If you want to play the game at high FPS, you should aim for a PC that meets the ideal system requirements listed in the article here.
So, if you are looking to purchase a prebuilt PC that meets these requirements, here are a few options to consider:
Lenovo Legion Tower 7i
HP Omen 45L
ASUS ROG Strix G16CH
If budget is not a concern, you can customize some of these pre-built towers at the time of purchase. For example, you can add additional RAM or upgrade the graphics card. The vendor will provide these options during the purchase.
Please note that I have only recommended devices that meet the ideal system requirements. Make sure you review and research any product carefully before purchasing a pre-built PC, especially since this is a higher-cost investment.