I have a fairly old iPhone and I never have much of an issue with speed, so maybe?
My main issues with Logseq on mobile is that a) there’s no plug-in support which makes my workflow much more difficult and b) I find the UI as just a copy of the desktop UI without many mobile-specific features usable but not super intuitive. If I need to jot down a quick note or TODO on the go I don’t think it’s best. I keep the app mainly to reference longer notes on the go.