15 years ago someone wrote a quick hack to do that, but it never got very far, and it was a bit unstable: https://forum.openmpt.org/index.php?topic=1819.15

OpenMPT's architecture doesn't make it easy to control it through another application, so there are no plans to implement this properly anytime soon.

just a heads up, it seems like none of those links work any more, so the hack might no longer be available, I remember checking out the vst maybe a few years after it was posted there, but I just opened it in ompt and it felt redundant so I never did anything with it... it might have been unstable as you said on that topic, but I dont think I ended up doing enough with it to experience that... if someone still has the hack somewhere to repost on the forums I guess that would be appreciated even though it will be a very old version of ompt... I dont think the copy I downloaded will still be on the computer I would have used back then, since I dont think I even have that computer any more... so I cant help there.

The binaries can still be found here: https://download.openmpt.org/archive/openmpt/1.17/OpenMPT_VSTi_0.2.zip - and yes, it's terribly outdated.