Based on a quick listen of the track you posted, I’d suggest that you might find the Empress Zoia pedal to be something of a dream machine for your post-rock/ambient needs. There’s no built-in song mode, but you might find yourself not needing one, instead preferring to “play” sequencers or button-triggered keyboards that you build up modularly and route to different things. You can put together the multi-looper pedal of your dreams with it, and in the same patch, have a chain of effects affecting the signal like a virtual pedalboard. There are a lot of existing patches people have made with very high-quality effects well-suited for post-rock, ambient, shoegaze, drone, and glitch.
So: no song mode, and not a complete DAW replacement, yet at least (there’s no recording to SD card, but a sampler module is planned for an update sometime this year that will allow for that), bit of a learning curve to get into the modular way of doing things (I might be understating this - I think it’s friendly enough to learn the ropes in a matter of weeks, but everyone is different), but the sky’s the limit beyond that.