I left my old 2018 installation intact, folder already called BIAB 2018, and moved only the AP RTs and Drumtracks plus some personal folders from that installation to a newly created BIAB 2019 folder after installing it. Then copied the AP RTs and drums folders from my PGmusic AP drive. BIAB 2018 uses those folders atomatically too, or you can redirect them there manually.

Reinstall your 2017? Name the folder differently than bb. PS i think if you own 2019, you're entitled to run 2018 as well.