iPhone 15 usb c to aux audio problem

My new iPhone 15 and 10th gen iPad have usb c, and, of the adaptors I've bought so far, the Apple usb c to female 3.5 will work as audio output only if I plug in the (non apple) headphones first (which now work consistently as long as the dongle is still plugged in), and leave the player running, THEN plug in the aud cable.

The headphone output of The third party usb c charge/headphone/usb adaptor does not work for headphones OR audio so far, but I can plug a midi keyboard and audio through the usb c and a ports, so I can get on with some music considering the batteries are new in both units.

i know this will get sorted in time but it’s frustrating when you’re creating art and you end up fiddling about with wires and software.

I am still on iOS 17.6.1… I always hang back from updating as it can upset the applecart when it’s multiple audio apps.

… so, has anyone updated to iOS 18 and found this problem to be solved?

thanks if anyone can help.