I've got a RAV Power RP-PC006-UK which is a 30W charger sold via Amazon UK. While Samsung recommend only using their products to charge the Tab A7 I have used the RAV Power for years with my Motorola G4 (also Qualcomm Turbo Charge compliant) and it's not screwed up the battery or charge circuit.
I tried it last charge with the Tablet and it works nicely without making the tablet too hot. It does charge in about half the time of the supplied Samsung Travel Adapter. The battery in the tablet is huge so takes the best part of 5 hours to charge with that 7.8W charger.