Loopy Pro: Create music, your way.
What is Loopy Pro? — Loopy Pro is a powerful, flexible, and intuitive live looper, sampler, clip launcher and DAW for iPhone and iPad. At its core, it allows you to record and layer sounds in real-time to create complex musical arrangements. But it doesn’t stop there—Loopy Pro offers advanced tools to customize your workflow, build dynamic performance setups, and create a seamless connection between instruments, effects, and external gear.
Use it for live looping, sequencing, arranging, mixing, and much more. Whether you're a live performer, a producer, or just experimenting with sound, Loopy Pro helps you take control of your creative process.
Download on the App StoreLoopy Pro is your all-in-one musical toolkit. Try it for free today.
Cadence - musical game on iOS
I just came across a short video for Cadence, which is a music puzzle game. Takes inspiration from apps like Figure.
It is a game first and foremost, so not a plugin or a full-blown DAW, but it seems pretty good nevertheless and may be a way to chill out while still keeping a creative focus. 
The game is free to explore and has a 4.99 € IAP to unlock the full version, and I still haven't tried it out, will play with it a bit after I'm done with work today.
https://apps.apple.com/us/app/cadence-musical-playgrounds/id970786199
Note: This is music adjacent, so I wasn't sure where to put it, please feel free to move it to a different section if anyone feels this fits best elsewhere.