I’ve just seen way too many new rifle owners, especially new AR owners, fall into this trap. One unfortunate consequence I have seen too often: One local indoor 100yrd range I often use has cable tracks as target runners, in a decade shooting there, I recall at least one instance each year where at least one of the lanes is shut down because some unwitting new rifle owner used a laser boresighter at home in their livingroom, then managed to shoot the runner cables because their rifles were zeroed a few FEET above target.
I offered one option above - sighting the optic to be 2.6” above the dot at 20ft, then shooting at 25-50yrds. Another option: actually boresight the rifle. Open the upper, pull the carrier, and sight through the barrel at the target at 50 or 100yrds. Zero the optic and the barrel on the target at the same time, dial up 4” at 100 to account for your cartridge’s drop, and fire at 50yrds. Either method works, same principles are applied in each case. It typically only takes me 5 rounds to confirm zero with any rifle, AR’s included.