You can deal with the imbalance by modifying the insole. Add tape or adhesive foam (e.g., moleskin) to give you the shape you want, that places you in balance and gives you a properly snug fit. If you have too a tight fit to add tape or foam, you could instead sand the insole down a bit. Or cut a completely new insole out of fresh foam. Either way, it only takes a few minutes, so it might be worth it even if you will have new skates in a few weeks.
It is conceivable that your skate tech moved the blade to the outside to compensate for your supination, without mentioning that he did so, when he shimmed things. That's very, very common. Unless you know for a fact that he didn't. He might have then shimmed to compensate for the resulting blade misalignment, and done the permanent mount.
The insole modification method I mentioned doesn't generally warp boots as much as mounting blades off-center, but most techs are taught to just offset the blade to the side. Easier and only takes a pound or two with a hammer, when you are still on your test mounts. Literally only a few seconds. It would NOT be considered bad technique to do so by most of the skating community.
Fixing the warp would be harder - but a heat mold might work. If the dealer will do it, there will probably be a charge - though maybe you can convince him he was at fault, and should do it free? If you do it yourself with a handheld hair drier, it will be free (assuming you have a handheld hair drier), but you may need to experiment a bit. It shouldn't be a big deal.
Incidentally, modifying Edea boots is supposed to be a lot more work and knowledge intensive (e.g., moving the blades would be harder, and you can probably count on your fingers the number of people in the world who are qualified to modify the shape of Edea boots), and Edea tends to assume a somewhat different foot shape. Maybe you should consider going back to Riedell, despite your unhappiness, especially since you say they fit otherwise? But it is your choice.
Honestly, if re-heat-molding would fix the warp, the type of issue you have had is well within what is common for skaters to deal with. Especially since these were not high enough level boots for your current skating level (an upgrade is appropriate), a break down over a year isn't all that bad.
Though, IMHO, if a skate tech doesn't deliver consistent sharpenings, that skate tech isn't worth using.
Maybe you could ask your coach's advice on your next skates...