I got a 16A dual voltage 'Duosida' brand EVSE for $175 from FleaBay, with free shipping. It has a 5-15 plug on it. The description often says '110-220V'...that is the indication it is dual voltage, and good with 240V.
It will run 8 or 12A (car selectable) at 120V, and 16A at 240V.
I also got a (cheap) 12 AWG extension cord, and put a heavy duty 5-20 receptacle on the female end (replacing a lit receptacle that would fail at 240V). I then made several adapters for 240V plugs to 5-20R for the other end.
You could get the same EVSE, and a 12 AWG extension cord for your case, and swap the male end for a new plug that fits your outlet.
I feel that 12 AWG is ok for 16A sustained, but this is not my everyday rig (its my portable rig). You might want to get a heavier 10AWG extension cord that is no longer than you require for your application. And if you can't find the plugs and receptacles you need (likely), swap them out yourself.
You would be able to get 3.8 kW EVSE setup for about ~$250. All the cords and plugs are on amazon.
Safety wise, the plugs and receptacles are the weak points....tighten the screws on the wires very well, and feel everything for any heating after some sustained use. None of the plugs or outlets should even be slightly warm. The other factor with extension cords is damage and abuse. Don't put it where it will get crushed or stepped on regularly, and if you see **any** damage, replace it.
Of course you could just do the cord/plug work first for ~$75 and see if the OEM EVSE (at 2.9kW) does the job for you. You can then decide later to upgrade the EVSE for $175. If you own the Bolt (rather than lease) you could then sell the stock EVSE to recover some of the $175 cost.