Can’t really answer, but if the library was available to all your Plex users, Tidal probably has countermeasures for that or maybe would ban your account.
Seeing 10 different songs (assuming you had 10 users streaming at the same time) being pulled from their servers from a single account would definitely raise suspicions.
Maybe you can get away with it if you have a Family type account with Tidal.
If there are only 2-3 of you, maybe it’s worth a try though.
I was/am in the same boat, but I quickly gave up for the following reason: Why bust my ass trying to give my business? If Lowes blocks me then f*ck em I’ll take my business to Home Depot. It’s their loss.