I'm not sure I've ever seen an accurate telescoping gauge...that includes one on an inflation attachment for compressors, not just the standalone pen ones.
Digital gauges sold for bicycles seem to be better, although I've seen some variation in those too. I imagine dial gauges are similarly accurate.
Mainly if a gauge is consistent then you can calibrate compared to something you trust, but I've never found anything worth trusting so I just choose one gauge and use it.
I've been happy with these (brand names and colors vary but the photos are obviously the same units as mine):