If you plan to have out of a QSFP28 some 25Gbps lanes as regular fiber to plug into a transceiver (SFP28) and some as passive copper DAC, that doesn't exist (to my knowledge).
Either you plug a QSFP28 DAC/AOC that breakout into 4xSFP28 of the same type, or you use a QSFP28 transceiver (SR4 for example) and you use a breakout cable MPO-to-8xLC, to connect to other transceivers (SFP28).