[haldean]

If you want a synth you can buy that has a similar playing style, you could check out the Modern Sounds Pluto: https://www.modernsounds.co/pluto (the original run is sold out but you can find them on ebay/reverb)

It's two of these 4-note step sequencers with some fun timing randomness. Similar to the OP's synth it uses knobs to set pitches but the knobs are picking notes from a specific key so they always sound good together. It's a lot of fun to play and doesn't require any musical knowledge!