(Bad Latency) iOS GarageBand & Steinberg UR22 mkII

(Using iOS 11.2.6 on my iphone SE 32gb and iPad Pro 10.5“ 64gb)

(With GarageBand v2.3.2)

I’ve been producing with a Steinberg UR22 mkII audio interface on my Windows laptop for a couple years and just realized the interface is supposed to be iOS compatible. However, connecting to either my iPad Pro or iphone I noticed audio crackling and a huge delay while monitoring and using my MIDI keyboard (Microkorg) making it impossible to play.

It seems there’s no way to change buffer size in GarageBand (2.3.2) as that‘d be my first solution. And an online search tells me this problem is consistent with iPad users.

Example Topics:

Midi latency with iPadPro 12.9 (2017)

Apple's iPadPro 12.9 (2017) has latency problems - www.steinberg.net

My question is if the problem lies in the iOS, the Steinberg UR22, or just GarageBand?

Would switching to cubasis fix the problem or should I consider buying a separate portable interface that works for recording with my iOS devices?