I found reading a dipstick on an E4OD to be very ambiguous and have overfilled at least once, which caused the trans to overheat. It cooled back to normal when I drained some out. I have a switch that selects engine or trans temp.
So I installed a sight tube. The tube I used is plastic, probably vinyl. Any sight tube is fragile, and plastic will degrade over time, and there is an exhaust pipe near by. The valve is only to be open when the tube is being read. After using the system the valve is closed and a plug is put in the end of the tube to keep out dirt. The tube plug must be out for the tube to read properly. Also fluid that is added does not change the level in the tube instantly. It takes a few seconds for the new level to settle.
Then all you need is something to plug the dip stick tube. It can be a dip stick, just the handle of a dip stick, a plug,,,.
Or, you could extend the tube to a more convenient location for filling, and maybe add a permanent funnel with a cap so you can pour directly into the tube and not need a separate funnel.
Running in park, with the trans warm, the fluid should be at the top of the pan, no higher.
With a fresh transmission, fill to the top of the pan, start the engine, gradually fill to a bit below the top of the pan. When you are sure the trans is warm, do a final check.
See pic.
https://photos.app.goo.gl/fFquy53SZ93WGecP7