Steinberg modified some protocols for program changes in VST3 and audio programs (Including BIAB) have to adopt for it to work properly. Some DAWs did, some didn't. I am certain it's very doable and likely would only require a line of code. Simon of PGM said they will look into this.
Halion/Sonic is in my view the best (most flexible) VST synth for GM/ Program changes. I hope they will figure this out soon.

However, second concern is to be able to preserve Halion6 if you have many older projects that use H6, as you will not be install it after May 2025 if you don't have physical key.