I recently had an award flight leg canceled DEN-ZRH-BER-CPH all in (I) with the BER-CPH leg being canceled.

I was rebooked over the phone onto DEN-MUC-CPH, UA/LH. Much better routing and I prefer Polaris seats for sleep so I am not complaining too much! However the MUC layover is 5 hours and there are 2 valid direct connections earlier in the day. One on LH and one operated by AirBaltic. These where not available a few days ago when I was being rebooked. I would love to swap to one of these, but the agents cannot seem to find availability in (I) even though it shows up on the website, both as a single leg and entire itinerary. I have tried both via chat and calling. To further complicate things when I go to rebook it myself, the website shows -0 miles paid and $42.xx when the actual was 88k so even if I was able to find what I wanted I wouldn't be able to book it myself.

Am I barking up the wrong tree trying to get a slightly better itinerary? Would UA agents need to reprice the entire journey to change the connecting leg? Is this an issue of phantom space or a HUCA thing?