According to the marked solution, domains are now supported in Feature Layers in Insights 2020.1. I have not yet tested this.
My planned workaround was a database view which combined the original table and domain table as part of the view, so you would see the original code and resulting value as separate fields. I haven't tried it yet, but probably will as I can see other applications of this (really anytime you want to use the table in a way not yet supported by live domain lookups.)
