Remember Easyjet defered alot of orders during Covid. I think existing orders go as far as 2029 so this is just 'keeping them coming' to secure delivery slots.
I do question what happens with the short haul model between regional airports. Can they fill 320/321s where a 319 works well.
Time to look at A220, I think they looked at E2 (paid visit to Luton during a Farnborough Airshow) but like most were put off by the economics. Seems to work well for Breeze in US.