Another good one doing IKEA compatible furniture parts is Superfront: https://superfront.com/. We use them for a bathroom cabinet in our last house.
Also take a look at Plykea for inspiration on what you can do with IKEA kitchen carcasses with custom fronts/sides/fillers: https://www.plykea.com/
During Covid my wife and I took six weeks off to refit our kitchen ourselves. IKEA carcasses, a lot of Baltic Birch plywood - all cut and finished ourselves - and half the fronts from uk company https://www.nakedkitchens.com/. It was a lot of fun, no one has a kitchen like ours, and all in it was under £6k for something that would have probably been closer to £40k if we had gone to a local bespoke kitchen company.