VoiceOver does not turn on when iPhone restarts

is accessibility shortcut turned on?
weird situation.

When I recently replaced my old phone, and did the automatic migration of everything, I had the same issue. I talked to Apple support, and they had me finally do a full reset of all settings. It worked, but then I had to reinstall and reconfigure everything. On a whim, after doing the reset, I tried restoring the last back up from my old phone, and everything was back, and Voice Over was working after a reboot.

If screen Curtain is coming on, that means Voiceover is not off, cause Screen Curtain is a Voiceover feature. The problem seems to be with the selected TTS voice which is taking time to download. Try doing the following:
1. Three finger tap to disable screen curtain so that sighted assistance may be sought
2. Go to Voiceover settings and try selecting a different TTS, select one of those that come preinstalled, such as Samantha. See if the phone starts talking then.

When I have speech on, I use the SIRI female voice. I had that problem too. I decided to try and use Alex instead as my default voice. When I turned the phone off and then on, it worked perfectly. So my conclusion is that SIRI voices are not coming on immediately.

I don't think my case involved downloading voices. Once the passcode was entered, Voice Over started talking. I used the phone for a day, with the Siri voice as my screen reader. The next day, as I was making changes, I decided to reboot the phone, and it went mute at the lock screen again. I was stuck without the phone talking for hours. Finally, was able to get sighted assistance, and the phone started talking immediately. Yeah, I was a little frustrated with my shiny new phone.

Once I did the full reset and then restored the last backup, things were up and running and it's been great since.

Well, except for the no speech after phone call bug that occasionally pops up. But I'm sure Apple is hard at work on that.

I can confirm, this happens when you use a Siri voice with voiceover.

There appears to be no way of getting past that lock screen unless you know your way around the keypad really well, or trust someone to enter your pin code for you.
This is where having something like internet recovery on an iPhone would be useful.

I had the same exact problem when using the automatic migration feature when setting up my IPhone SE third gen. I ended up having to put my phone in recovery and restore from backup since I did not have anybody sighted with me. I was not using the siri voices so I don't think it's related to the siri voices. It must have something to do with the voice transfering or something is going glitchy. This in my oppinion should be flagged as a serious bug in the list of bugs.