Heat disposal and special purpose electronics for both reliability and ability to survive both launch vibration and on-orbit heat and radiation will make this impractically expensive.
The question is: why is this being pushed publicly?
You picture a data center as four walls shoved full of servers. You should picture instead a gpu + ram + cpu upgrade for a starlink plus node with compute capabilities. Now rinse and repeat a million times.
Can starlink work? (Proven) Can starlink increase their solar power and heat distribution capacity by 50% (probably) Does starlink have fast, redundant data connections within the cluster and between the cluster and the ground (proven)