Issues with Folia 1.20.6: I'm aware of the problems BreweryX is having on Folia 1.20.6 and I'll do my best to send out a patch for them as soon as I can in the next few days or so.
Mojang changing "GRASS" to "SHORT_GRASS": I've resolved this and set BreweryX's default config to use "SHORT_GRASS". BreweryX will also not throw errors and will still recognize "GRASS" as "SHORT_GRASS" now.
Scriptable Potions: I've been working on this for quite some time, but I've submitted a pull request to have BreweryX's API be implemented into Depenizen. You're welcome to check the status of this here: DenizenScript/Depenizen#430