Brush tool sizing issue

I'm having an issue where the brush size (when painted onto the canvas) isn't matching the brush size that I've defined in the Brush panel. I've been using Photoshop for decades, and I thought "I'll just increase the brush hardness."  But the issue persists. I've tried changing brushes, but it doesn't matter which brush I choose, the pixels it lays down is always about 20% smaller than what I've specififed.

Granted, I don't have a ton of experience using brushes in a creative sense, but up until today, I've always been able to paint a circle in the size that I specify.  What am I missing? 

I am running PS 25.7.0 on Mac OS 13.6.6

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