Please explain to me how to succesfully print PETG on a PEI build plate.

[Bikeracer2020]

By the time it gets about 2/3 of the way through the third side of the first line, it is pulling the first and second lines behind it like a dog following on a leash, No balling, no fuzzing, just won't stick..

Sounds very much like the nozzle is slightly too far from the bed.

Suggest.....Print a 50mm square just one layer thick and adjust the 'Z' offset in the slicer plus or minus 0.01mm, whichever brings the nozzle closer to the bed.
Remove print and see if each extruded line is stuck to the adjacent one, if not, then print again but alter the 'Z' offset by another 0.01mm or 0.02mm to lower the nozzle until all lines are stuck together.
If you start getting a rough sea effect the nozzle is too close.

230 nozzle temp seems a bit low. Perhaps increase the nozzle temp to mid way between recommended temps for your PETG.