I have not had any luck with glue. I have had some success with melting more plastic into the hole with a soldering iron but if you make a mistake you need a new tank.
I have had the best luck with these threaded inserts. I am not sure if this is the exact size I used or not so buy a few sizes and find the one that is slightly larger than the hole size.
https://www.homedepot.com/p/E-Z-LOK-...0-13/304618041
I think I used a 1/4-20 version that was in stock at home depot. They are too long so you will need to cut down the length to match the hole depth.
You may need to remove the rest of the original plug before you install the insert. I used a bolt and jam nut with the insert as a driver to thread it into the tank hole.