No, linking to a static version of the CRT is a good thing, it cuts out the unused code. If you dynamic link to MSVCRxx/VCRUNTIME, you force the user to download that exact DLL from Microsoft. Dynamic linking to MSVCRT doesn't have that problem, but it's very hard to do in Visual Studio.
The only time you really can't static link to the CRT is LGPL compliance?
Windows has been shipping an up-to-date, modern CRT in the box for a decade now (Win10+), and MinGW will even dynamically link to it by default. Even on out-of-support OSes like Vista and Win7, users who have all the security updates installed will have it. So you have to unwind all the way back to WinXP for a version of Windows that doesn't have uCRT out of the box.
There's absolutely no reason to statically link CRT in a Win32 app today. Especially not if your goal is to minimize .exe size.
It looks looks mingw actually has several options to base its own CRT on (including MSVCRT, UCRT and various VS runtimes). Still, in the context of OP's original post, we are talking about the mingw DLLs that may or may not redirect most of their duties to Microsoft DLLs, depending on how mingw is configured.
The only time you really can't static link to the CRT is LGPL compliance?