That would work, with the understanding that you're going to be limited by the 30 amp rating (then have to derate it to 24 amps for CONTINUOUS usage) of the PDU.

 Most PDUs are designed to work with a L6-30 because that's by far the most common power feed in most data centers.


 There is no "loss of power protection" in setting up a BREAKER BOX to feed from that outlet and split it out into smaller circuits - in the NEC it is called a "secondary panel" though most such are hard-wired, not plugged into an outlet.

 This used to be a COMMON setup in Mobile Homes (but was the PRIMARY panel there), feeding from a L14-50 for the entire home via a (usually) fairly long cable to plug into a pole-mounted outlet box - the usage is depreciated in recent code versions, but it still allowed in "existing" installations.

 A 40 amp 220 circuit will split out to 4 x 20 amp 117 VAC circuits safely, since the L14 provides the center tap "neutral" connection to do so.
 Or you could set up the secondary panel to provide 234 VAC instead, though 10 amp 234 VAC breakers are hard to find you could do a pair of 20 amp circuits, or a pair of 15 amp circuits (for the miners) and a pair of 10 amp 117 VAC circuits for other stuff that needs 117 VAC.