Cork has traditionally been a tough market to make money in, but there does seem to be improvement. The Ryanair and KLM announcements are in the context of capacity shortages in the networks, so that is a positive sign. At the moment Cork seems to be doing very well and there is good diversity in the recent additions, in terms of airlines and destinations.
You're right, it could be swings and roundabouts in terms of adding A220s. The A220 really is a different machine to anything previously seen in the size class and that potentially opens a lot of opportunities for airports like Cork. It has comparable per-seat cost AND trip costs as an A320neo/737-8MAX, but carries ~140 passengers. If Ryanair had something a bit smaller would the Liverpool schedule be more attractive, for example?