TouchOSC 4+

I can’t bust the devs for iOS idiosyncrasies, and the app is, as others have mentioned, almost there. But… I struggled for a couple of afternoons with a 2021 iPad and Windows 11. For whatever reason, usb wired or wireless the app would work, and suddenly stop transmitting. I never got the mirror editing from desktop to work. Which doesn’t matter and the desktop nag screen is a pain. I got fed up, plugged a MIO MIDI interface into the iPad and into the DAW of choice, not a single glitch.
So if you’re cussing this app on iPad or phone, or playing a real gig where wireless and BT aren’t options and wired maybe works for you, maybe doesn’t, pick up a cheap used iOS MIDI interface.

Great app, the panel menus are pretty clunky but eh whatever (It’d be nice to have notes instead of numbers for midi note-on values etc.), and being able to copy and paste messages instead of entire controls would be huuuge (copy/paste parameters from/to different controls) but there’s 2 things that keep it from being truly amazing...

1. Attack and release values for local-data and midi cc’s, as well as the ability to ADD TO and SUBTRACT FROM (not just SET) cc and other values (prefer hermmutt lobby’s beatsurfing app from 2013 for this reason). Ive spent a few hours with the Lua scripts and it’s not worth the effort for time based effects like this (may as well use max for live).

2. The ability for touch to pass through and hit multiple controls at once (not just the on that’s on top). No longer making "capture attention" required was a HUGE improvement (made it possible to make surfable/strummable instrument designs), but it’d be even better if you could hit both controls at once when they overlap.

Pretty fantastic app once you get it set up.
I just built a custom layout that is sent to my computer, and then back out via midi usb to my modular synthesizer. Super fun having four XY pads sent to filters and envelopes of my hardware synths. It was a bit confusing to get started however. And as far as syncing with logic pro, it seems like 50% of the time, it just won’t work. Could really use explaining the relationship between OSC and logic controller mappings. The manual is very matter of fact and could really benefit from small tutorials/step but step. OSC mappings really don’t make any sense to me, yet.

For my midi hardware setup, I just put the time in comparing the preset layout parameters to my custom layout. Soon enough it all started to make sense (midi). The editor is easier to use on the mac, but easy enough on mobile device. I recommend to anyone looking for a solid alternative/companion to your midi controllers. There’s definitely deep potential with this platform. Take it as far as you’re able/comfortable