I believe that the other two new builds are for the Birkenhead to Belfast service.
Stena Estrid has entered service on Holyhead-Dublin and now Stena Edda is starting her journey from the builders in China having been accepted by Stena Line:
https://www.niferry.co.uk/stena-line-tak...ead-ferry/
Vessel is due to enter service on Birkenhead - Belfast route in April.
Stena Edda up-date:
https://www.niferry.co.uk/stena-edda/
Vessel due to enter Birkenhead-Belfast service in late spring giving increased capacity for freight as well as passengers.
Good reviews on line for Stena Estrid which entered service Holyhead-Dublin in January 2020.
STENA EDDA is now on berth at Birkenhead to test systems including the new double deck ship-to-shore ramp. No doubt will be seen by many viewing the aircraft carrier (HMS Prince of Wales) that is on the Liverpool Cruise Terminal berth. Stena Edda is due to enter service on Birkenhead - Belfast in the next couple of weeks.