We love all of them, so I don't think you can go wrong with any of them. One thing to note is that CSR's QS food court is not currently open and they are not currently selling refillable mugs. Its possible this could all change by January, but something to keep in mind.
We just returned from a week long stay at CBR. We chose CBR because its at the Skyliner hub, and DHS has been the most consistently busy park in the mornings. Even though the ROTR boarding process has helped to alleviate some of the crowds, its still busy to get there in the mornings on Disney transportation. Coming from AOA or Pop, you have to transfer at CBR, so staying right at CBR gives you a bit of a lead and you only have to wait in one line as opposed to two lines (one at Pop/AOA to board the Skyliner and another one at CBR to board the DHS line).
Another reason we chose CBR is because we only had to bus to 2 of the 4 parks. Coming from CSR, you'd have to bus (or use Uber/Lyft) to all 4 parks. Even though CSR has limited capacity right now, the buses have severely limited capacity. There was more than one instance where we had to wait for another bus to come around, and this is particularly problematic in the mornings when bus depots are busy and everyone wants to be there by park opening. We ended up using Uber/Lyft to MK and AK from CBR, so I personally would want to avoid having to be reliant on buses for all 4 parks until social distancing is no longer required.
The last reason we chose CBR is due to the proximity to Riviera. It was a very close walk so it gave another bar option, another QS option, and its home to one of the few character TS meals currently operating.