There’s no upsampling happening in Roon here. This is a common point of confusion about MQA–the 44.1kHz means is that the master recording used to make the MQA file was 44.1kHz. In their terminology, 44.1kHz, is the “original sample rate” of the master.
The MQA file still contains a stream at 88.2/96kHz. When we decode the file, we are decompressing the file to that resolution. All MQA files go through the same decoding process in Roon, regardless of the sample rate of the master recording that was used to make the file.