I bought a 4 from TB thru 2 sellers. 1 QC port become slow charge, 1 QC working but other 2 ports super slow charging, 1 QC still working, normal port became slower, last 1 rarely use, all working for now. Lucky got if cheap like $7 each. The heat generated with you charge using all port is terrible, probably the reason for failure.
on good side, 3 of them still have QC working. so using them as single port for the past 1yr+
Don't worry so much about cables. using China brand 2 for $3-4, working on all my devices and charger for past 2yrs. Modern phone is able to cut off the charge once full.
Posted from PCWX using Redmi K20 Pro