This. In the woods, especially on twisty singletrack, while there’s full leaves on the trees, can give comically inaccurate GPS data. A speed sensor helps a lot with getting accurate speed and distance, even if the bread crumb trail is wrong.
If you’re mainly riding on roads with good visibility of the sky, you will get most errors evening out.
Also, not all GPS is equal. First there’s different services (plain old “GPS” run by US military, GLONASS, Galileo, etc). Second, the computer you use has some effect on accuracy. So do things like weather. So there’s several factors at play.
Chances are It’s going to be more than fine for your use. Even if you get a bad data point, there’s ways to fix that with GPX or FIT file editors