Hello Salar,
Thank you for posting question on Microsoft Windows Forum.
Actually! You can upgrade all your PCs from Windows 11 Home to Windows 11 Pro at once, and the easiest way is through the Microsoft Store. The upgrade license costs around $99–$129 USD per device, and once purchased, the upgrade applies immediately without reinstalling Windows.
Please refer to this article for more information https://support.microsoft.com/en-us/windows/upgrade-windows-home-to-windows-pro-ef34d520-e73f-3198-c525-d1a218cc2818In your case, if you have multiple PCs, consider Microsoft Volume Licensing or Microsoft 365 Business Premium, which includes Windows 11 Pro rights. This will allow centralized management and avoids buying individual upgrades one by one.
You can consult below article for more information.
Hope the above information is helpful! If it is. Free feel to hit "Accepted" for benefitting others in community having the same query too.