SneerClub

You're right. I don't know if the EU could actually stop Italy from creating an independent city-state within its borders - probably not. But TechTopia would have to either join the EU and submit to all the legal, financial and tax obligations.... or negotiate a trade deal with the EU from scratch.

Negotiations between the EU and Britain, which is an actual country that only has 1 EU land border, ended pretty badly for Britain. I can't imagine them even being considered for a tiny city-state with no resources that's entirely surrounded by another EU country. There are states in Europe that aren't in the EU, but they're either states that are trying to get into the EU or independently wealthy states like Norway and Switzerland that pre-date the existence of the EU and have negotiated agreements with them over the decades. Plus Italy would probably get punished by the European commission. I don't think they would have even considered it.

You get the impression they've done absolutely no groundwork on the places they want to set up their cities. I assume it's a scam and they don't actually have any intention of setting one up - but maybe that's being too generous.