Since Windows 7 reached the end of life in 2020 and it is a limitation of GDI+ on Windows 7, especially when rendering private fonts (PrivateFontCollection) at large sizes, you want to try maybe the alternative

• https://learn.microsoft.com/en-us/windows/win32/direct2d/direct2d-and-directwrite (Text Rendering with Direct2D and DirectWrite). Try to see if this works out for you.