Your problems why you are stucked:

• to many lvl 50 champs, not enough lvl 60 champs
• champs not ascended

I don't think stages between 20 and 25 are worth farming, they have to be completed only once to progress. If you can't beat stage 23 yet, go on at stage 20 until you have better gear. And lvl up some champs and ascend them.

Stage 20 is magic affinity, the following team should have no problems in farming it: Kael, Dhukk, Ronda, Scyl, Geomancer.

Above stage 20, the enemies in the waves are not as weak as before and have tons of hp. Urogrim helps a lot to beat these stages, poison becomes very strog in higher dungeon levels. With top equip, he can even solo Dragon 25, but that's probably not a thing for now, he would need a regeneration set with fantastic stats to do so.

Dragon 25, if you reach it, is force affinity. A team of Urogrim, Geomancer, decrease def champ with matching affinity (Tayrel and Dhukk are both weak vs. force), Yannica (damage dealer vs. waves) and Rhazin should be able to farm it in reasonable time. All champs lvl 60 with masteries and full ascension, of course.

Awesome, thank you.

I have enough food to get 5 champs to 6 star. I have been waiting for this CVC.

Looking at the list of champions you have mentioned - I think Ronda, Scyl, Warmaiden (decrease Def Force affinity), Yannica and Rhazin should tick the boxes. With Urogrim following shortly afterwards.

That should then allow me to farm Stage 20 with Kael, Dhukk, Ronda, Scyl and Geomancer until I have enough gear to farm Dragon 25 with Urogrim, Geomancer, Yannica and Rhazin

Thank you so much for giving me a target to aim for. 

I would lvl up Urogrim first instead of Warmaiden. Maybe you get a better debuffer from a shard until you reach Dragon 25. Then you would sit on lvl 60 Warmaiden that is not used anymore. If you are not lucky enough to pull somebody, you can still go with Warmaide and use her in faction wars as well.