Me again. This is sound advice. I have owned a myriad of air pumps over the years both hand operated (bicycle pumps) and electric.
I have never received one with an accurate gauge on it. Never ever, not once in decades.
The one I currently have living in the trunk of my car is a Slime branded "heavy duty" pump with an all metal housing that's held up remarkably well over the years and has bailed out many a poor sod on the side of the road along with my plug kit. Its gauge is off by like 10 whole PSI and it has been since day one. It consistently over-reports, so if it says you're at 30 PSI you're actually around 20. I keep an old Ingersoll-Rand dial gauge from the 1990s in the zipper case with it that probably cost me about two thirds of what the pump itself did. but I have to, because it's actually accurate.
My ostensibly nice bicycle pump is off by about 7. The regulator on my shop air compressor is pretty accurate, but that's a pain in the ass. Pencil gauges are useless. Don't even consider one, not for 79 cents and not for five bucks.
For working on things the garage I have a digital gauge. The only downfall with these is that they'll drive you nuts with eating batteries all the time. If you don't need portability, do yourself a favor and find one that takes AA or AAA cells instead of watch batteries. For field use I have a tiny button cell powered one that takes two LR44s, and I've just resigned myself to having to replace the cells at the beginning of every season.
None of this should be this difficult. It's downright irritating, I'll tell you what.