iPhone speed panel disappears

I presume you're talking about the Traveller app.

On my Samsung S21 Ultra (Android) it works as it should. Maybe it has something to do with screen size. According to the table here your phone's screen is 157 x 77.Mine is 163 x 75. Maybe that 6mm difference in screen real estate makes a difference - David or Michelle may be able to advise if they see this. (They are travelling ATM.)

Do you have the latest version of Traveller installed - 7.3.3?

How and why to reset the position of the Speed Panel is covered in the FAQ section of the ExplorOz Traveller webpage (and yes we're on the road so forgive my lack of more detail finger texting in car). Also covered in the User Manual.

Following from Michelle's reply above, here's what is in the user manual:

The panel has two defined settings for Portrait & Landscape so you can turn your phone/tablet either way and the panel will adjust position. If you’ve changed the default position of the speed panel however, you may not see it when you go to the other orientation. To fix this, reset the panel back to the default settings by going to Settings – App Resets – select Reset Speed. Then turn the device to the preferred orientation.

Cheers