It’s not hard. It’s power intensive. It’s $15k/mo at 15 cents / kWh. If you want the experience there’s a massive A100 liquidation sale that happened recently https://www.ebay.com/itm/178522410497

These come around once in a while. Go get that seller’s Gaudi rig if you want to test the experience. It costs one-time as much as the monthly power cost on a B300 NVL72 and uses a fifth the power.