Official bladeRF forum

To get higher speeds, you need to use FPGA oversampling (8-bit mode only works), but you can't just set the samplerate in the CLI.

On bladeRF 2.0 the 8-bit bitmode only reduces USB bandwidth and does not raise the RFIC clock limits, so rates like 80 Msps or 92.16 Msps are simply outside the allowable samplerate range (≈61.44 Msps max per channel), which is why only 61.44 Msps works.