You sound a bit like me, I’d say the A4 could be a good choice.
It’s interesting to read @ligature 's experience because I’d say almost the opposite! It’s essentially 4 dual oscillator analog monosynths. If that’s a sound you like then I think you’ll get on with the A4. I don’t struggle to sound design on it any more than other monosynths, personally - with each you got 2 oscillators (each with multiple sub osc options), 2 filters, and multiple modulation sources - you get everything you’d expect with a monosynth and more. Being an Elektron box there’s lots of additional power when sequencing but ultimately that’s what you’re dealing with. You can make it as simple or as complex as you like.
It’s very versatile within that framing - and if you want ‘traditional’ analog sounds it gives you them in spades. Tearing, detuned thick sounds come with ease.
I’ve been learning to work with my Digitone but I often have to fight its character and struggle finding the sweet spots. So far I’ve never had to do that with the A4.