Bluetooth reconnecting issues with non-Apple devices on iPhone 15 Pro

First step is to forget the devices, and then re-pair them.

Perhaps a long shot:

Do you have a 3rd party VPN installed, even if you are not using it? If so, delete the VPN profile in Settings/General/VPN & Device Management/VPN, then restart your device. Don't just turn it off; delete the profile. If that fixes it, you can try reinstalling VPN, but probably shouldn't.

M1-k3 wrote:

I've tried to delete VPNs - didn't help. Even if it did I find it very strange for not a cheap device to do this kind of "workarounds".

I'll try to report it as a bug (if it's even possible)

You've "tried" to delete VPN profiles or you'ave "actually" deleted them? I have loads of Bluetooth devices on my iPhone under the very latest iOS version 18.6.2. None have any intermittent connection issues. But then, I don't, nor would I EVER install a useless VPN profile on my iPhone. To remove the Profiles completely, did you go to Settings > General > VPN & Device Management and completely remove the Profiles there? I'd be willing to bet if you do, you'll not have any connectivity issues going forward.

VPN, when installed, is configured to the specific hardware, networking and operating system version. If any of these change the VPN configuration is no longer valid, and it may be necessary to delete and reinstall the VPN.