I can’t think of a single instance where a manager has successfully rotated goalkeepers.
England tried it briefly with Shilton and Clemence in the 80s and it was soon dropped. Brighton have apparently been doing it a bit this season. But it doesn’t look like it’s doing them much good.
No matter how similar in quality they might be, the manager must always slightly think one is better than the other at any given time.
Ederson is No. 1 and I’m 99% sure he will be next season. If Ortega can’t live with that then off he pops and we find someone else as backup.
As you mentioned, Brighton are the best example who have rotated completely evenly split between Verbruggen and Steele. Crystal Palace have rotated keepers this season, mainly between Johnstone and Henderson.
Arsenal planned to do it this season, if you take Arteta for his word, but it didn't work out that way. Newcastle did it a bit further back in multiple seasons.
Burnley kinda have this season but also more genuinely did it under Dyche when they had three England internationals (Heaton, Pope, and Hart), and another time when they had two England internationals and a Northern Ireland international (Heaton, Pope, and Peacock-Farrell), all getting game time in goal.
We've had dilemmas in the past, and in those situations we either opted for a complete 1st choice, or just given the number 2 enough time as not to complain. Given vs Hart, Hart vs Pantilimon, Hart vs Caballero.
Ortega Moreno is very strong, Ederson is world class. I'm sure that the ever-growing schedule gets on top of Eddy sometimes, just as it does with our (other) outfield players. A somewhat even split between Eddy and Ortega Moreno could work out brilliantly, or could go south. I recon it's worth trying out though. Pep can always have a chat with his mate on the south coast and ask him what it's like.