I use Prism Launcher, which is a fork of MultiMC and fully compatible with its instances. Currently, to install Vivecraft into Prism, I have to install MultiMC, create an instance, run the Vivecraft installer, and then copy the instance to Prism Launcher. If I try to point the Vivecraft installer to my Prism installation, it assumes it's a vanilla Minecraft folder and just jams folders and files into Prism's install directory.
I use Prism Launcher, which is a fork of MultiMC and fully compatible with its instances. Currently, to install Vivecraft into Prism, I have to install MultiMC, create an instance, run the Vivecraft installer, and then copy the instance to Prism Launcher. If I try to point the Vivecraft installer to my Prism installation, it assumes it's a vanilla Minecraft folder and just jams folders and files into Prism's install directory.