I’d say your best bet is a commercial filter coffee machine and commercial packs of pre ground to go with it. There is a selection of tastes available and some would seem ok to typical espresso users if they drink coffee with milk.
There are 2 basic types. One has a hot platform to keep a flask of coffee hot. Probably not ideal as a fresh flask can’t be prepared without removing it. Another type is designed to work into pumped thermoflasks. Probably takes ~20min or so to fill one. This sort of thing
Packs of grinds are available to suite the size of machine, Suppliers of these packs probably also supply machines. Not suggesting the one in the link just what I think would suite you as the ability to use an espresso machine doesn’t come quickly and a commercial machine plus a suitable doserless grinder is outside your budget,