Is there a usable image-bitmap editor (e.g. app icons)?

I develop apps for iOS and other Apple platforms, and I need an image editor to create icons: 1024x1024 pixels, ideally from vector tools in transparent layers. Pixelmator Pro and the current iteration of Sketch are completely unacceptable.

I need something that stays in its lane: It creates bitmaps. It should use layers, including vector layers (mathematical paths that get converted to pixels on output). Where is that tool?

(I've reduced my critique of the current state to "feature-brag," "2005 Powerpoint revival." "Getting Started" tutorials — five starting points each leading to two easy pages of click-by-click instructions (many spelling-out three equivalents) to display an empty document — is a Bad Sign. So no, publisher, reciting one of the 4^30 paths is no rebuttal.)

This is what I mean by "stay in your lane."

What can I use to generate incidental art, ideally from commands that can move shapes, use consistent coordinate systems, pour a color into the counter of the letter O, and place the whole thing on a transparent background?

There's nothing obvious in the Mac App Store; maybe I'm overlooking a gem. Now that I've seen what's become of my go-to tools, I'm willing to pay real money.