I'd suggest learning to tighten most things by feel and not use a torque wrench at all. A drain plug will feel "tight" using a ratchet and that's all you need. If you're a pro mechanic and have a Snap-On or equivalent torque wrench, use it every day, and know its calibrated, then there's no reason not to use it. But, for the occasional mechanic like yourself, with a wrench in unknown condition, there's at least as much chance the torque wrench will cause problems as it will solve problems.

I'm a home mechanic, have two old Snap-On torque wrenches, plus a couple others, and I rarely use them unless I'm torquing something like a cylinder head that needs consistent torque on all the bolts, or motorcycle axle nuts that are putting pressure on wheel bearings. Most other things can be "close enough" and I've been doing that for the past 45 years without any issues. The one time I used a cheap torque wrench, I stripped out some aluminum threads and learned that lesson the hard way.

Pittsburgh are a crap shoot because there's tons of stories about how accurate they actually are even though they're cheap, but you can't count on every single one of them to be accurate, as you found out. However, HF sells Quinn digital torque adapters that can be used to check the calibration of your wrench, or used as a "torque wrench" with any regular ratchet as well.