I've just googled PuC and I'd bet my house on Cork not happening.
For one thing it only has 21k seats and converting terracing is not a simple matter of bolting on a few seats. And for another, its barely one third under cover - UEFA doesn't do open seating. Third, it almost certainly doesnt have the extensive VIP, Corporate, Sponsors and Media facilities necessary to stage such an event.
Look, for example, at the hoops the FAW had to jump through to stage the 2017 CL Final at the Millennium i.e. one game on one day:
https://www.walesonline.co.uk/sport/...pions-12928557
Meaning it would take tens of millions to get Cork up to standard and there's no way the Irish government is going to plough any more into that stadium, while UEFA awards tournaments to countries in the knowledge that money will be spent developing soccer stadia, not those of some other sport.
Above all, there's no way the English FA (or its Westminster paymaster) is going to tell eg Bristol or Leeds that they cannot host a Group because Cork GAA has got it. Forget it.