I’m still at the moment using my iPhone 8 to run SD as only just started out doing a few NAV trips. It’s great and use a holder on the dash.
Only annoying thing about using a phone for navigation is when your coming up to a crucial turning point near controlled airspace and your map disappears as the Mrs tries to call you!
My plan is to get a refurbed iPad mini 2 or 3 4G so it has GPS ( also think the 1st iPad mini doesn’t software update enough to run SD now) from sites such as musicmagpie, amazon or similar with a year warranty. Use the iPad mini on a knee pad for SD and my iPhone 8 as a Directional Indicator.
The only heading aid on my aircraft is a compass and despite UNOS and calculations my compass turns seem very inaccurate even when straight and level! I remember how annoying I found it to keep slaving the DI on a C150 but realise now how much I took it for granted compared to just having a compass.
Really I want another device to back up my iPhone as still backing up on the old maps.