Whatever your ecu is, is the best one to use. There's lots of def files for the 1.8T on here so all you'd really need to do is get an xdf of similar and any of the main maps you're going to use, you just change the data location so it lines up - fairly straight forward!

Alternatively if you must cross flash then look into your sw rev and see what people have used and works and that'll be the best one.

I tried to do a little explanation on the lining up of data or a lack of data on an xdf depending on what tools you use/protocols etc here;
https://www.vr6oc.com/forum/forums/topic/50563-v6-4mo-24v-bde-tuning/

You can send me your modded bin through pm to see what looks amiss or put your ori up and I'll pick out the pertinent locations for most/all of a tune if you want when I can spare some time? I used hn on my own a few years back, virtually stock AUQ Cupra. Few aspects of load to consider, logs a bare minimum to make sense of.