On the SEU issue I’ll add in that even in LEO you can still get SEUs - the ISS is in LEO and gets SEUs on occasion. There’s also the South Atlantic Anomaly where spacecraft in LEO see a higher number of SEUs.
Everyone keeps talking past each other on this, it seems.
“Generating power in space is easy, but ejecting heat is hard!”
Yes.
“That means you’d need huge radiators!”
Yes.
OK, we’re back to “how expensive/reliable is your giant radiator with a data center attached?”
We don’t know yet, but with low launch costs, it isn’t obviously crazy.