How is your grouping at 20yrds
Michael,
How is your grouping at 20yrds. If you draw a circle around all our shots (say you shot 3-5 times) would the circle have a 1in diameter? 2 inches? 5 inches? Based on your answer to this question you will receive better advise for improvement.
For instance if you are within 1-2 inches but happen to be 6 inches left and below the bulls eye you will improve by zeroing the rifle at the distance you want to shoot at. If you are 5-6 inches and sort of all over the place then you need to work on controlling the rifle OR the sights are not tightened down. Determining if your guns sights are tightly secured to your AR is easy. do that anyway.
Also, learn to shoot and control the gun without the EOTech optic. Don't misunderstand, Red Dots (and EOTechs specifically) are excellent for fast target acquisition and allow the shooter to keep both eyes open for improved depth perception and peripheral vision. Red dots are not ideal for replacing skills and fundamentals.
Iron sights are reliable and will always work even when you forget to change the battery in the red dot. Iron sights are very accurate and have been used by sharpshooters for years, decades, even centuries. If you learn to shoot with open sights you should be able to translate the skill to shooting with optics without a problem.
You should not need a red dot or a scope to see the bullseye at 20yrds, some people need corrective lenses of course, but a gun optic isn't a solution for that. You should not need a bench or other rest to learn to shoot within a 1"-2" group at 20 yards. You shouldn't need a sling to accomplish this grouping either. Once you get the fundamentals down, the slings and optics may help you improve further but in the beginning they could easily become a hindrance as you are adding more variables to the equation.
Apply the KISS method, (Keep It Simple Silly). Practice gripping the rifle with the same hold. Practice consistent Cheek Weld (placing your cheek tight against the stock). Practice your breathing control, Practice squeezing the trigger without moving the rest of your hand on the grip. Others (likely superior shooters to me) have given you sound advise on this topic already, my advise is to heed their advise.
If you are able to do these things, then you should become consistent with your shot placement. Once you are consistent you will know where the gun is shooting at whatever distance you choose. Learn to shoot 20 yrds (or meters), 50 yrds an 100 yrds. Don't bother trying to obtain accuracy at 300+ until you've mastered the shorter distances. If you are only going to shoot at 20 yrds and want to use the riffle for Home defense then it may be reasonable to zero at your local indoor range.
Good Luck to you