iOS simulator version doesn't appear - Xcode 12.2

After a lot of research I've tried to add a simulator via terminal using "xcrun simctl list" to list the simulators available, one of the infos returned is:

iOS 10.3 (10.3.1 - 14E8301) - com.apple.CoreSimulator.SimRuntime.iOS-10-3 (unavailable The iOS 10.3 simulator runtime is not supported on hosts after macOS 10.15.99.)

It's look like sadly the macOS Big Sur 11.0 doesn't support the iOS 10.3.

I think it could be a bug and the Xcode shouldn't allow the download if this iOS version it's not supported, I found in the apple forum that in other macOS versions some thing like this error occurred, see more in the link below.

https://developer.apple.com/forums/thread/74848

Thanks @matt for the support, I really didn't know that I could answer my own question.

I’ve got some more information on this: When I right-click the devices in Window -> Devices, "Show in Run Destinations Menu" is checked on all the Simulators just like it is on my real devices, yet only the real devices show up.

Also, I just tried creating a new iOS project from scratch, but there was no option to run anything at all. I don’t even know how to set this up, though, because I use Unity for creating Xcode projects. But I can confirm that this issue shows up on all the Projects that I am working on. So it doesn’t seem to be project-specific.

Besides, when I updated to 6.2, the simulators still worked in 6.1. Only 6.2 was having this issue. Well, and then 6.3 and now 6.4.

In one of my previous posts I answered the problem has been resolved to some extent.

But ultimately I was informed everything on Xcode's side worked as expected.

The bug was Unity-related. There has never been an option to run a Unity build on both simulators and actual devices.

There was a bug showing the simulators even though they were not available.

Now everything works when building for simulators in Unity.