But to be fair, the limiting factor on earth was that it got much hotter much faster than scientists had expected. We aren't likely to have that issue on Europa.

Rather than having to keep the drill bit cool, to drill through ice you could use a heated drill bit. Perhaps using using radioactive material to heat the drill bit and cut through the ice like a hot knife.

(Of course, irradiating an alien ocean is perhaps not the greatest idea ever.)

It sounds to me like Elon Musk needs to combine efforts between SpaceX and The Boring Company.

Radium-knife: cooks the steak while you slice it!

It also means launching a large amount of radioactive material through the atmosphere which may end badly

The advantage on Earth is that you have dozens of machinists, operators, labourers, and tens of thousands of tonns of supplies necessary for digging these holes.

You can't do that with one robot, and a weight budget of a few tonns.