I'm thinking of how to do that automatically. The SDL2 patch refuses to apply cleanly, but I'll give it a try.

see in my signature, I've now an up to date SVN built and I'll try to get that going. Any change to the SVN might just break the patch and that means I'll need to adjust. Thus the SDL2 snapshot might not be always current. But at least close to it.
It uses a new config (DOSBox SDL2 Preferences) and has the output Texture instead of overlay, also a vsync option and a renderer option. Beware, do not use renderer Metal (or auto) with the output texture -> output is distorted (the prompt is black). But output OpenGl is the fastest anyway 😀

That is really great, thanks for investing the time to set that up. I hope that it will get easier to apply the SDL2 patch in the future, so that it is not too much trouble for you to maintain it.