This way engineers can actually see the scale, investigate. Keeping it, in this old thread doesn't help anybody.

Nothing shared here is working, this issue has to be fixed, it's ridiculous that this still happens after years.

I found a solution th the problem described by OP.
When your phone is on the "Follow thee instructions on other device" screen, just press the "Overview"(switching apps) button and force-close Opera. When you relaunch opera on your phone, flow should be already connected.

It worked for me, it may not work for you, but i'm trying to help as much as i can.

So this didn't help at all cuz when I scan PC QR code with my phone, and force close it does nothing.

But I found another solution. that may help
The problem was a DNS server, I'm using NextDNS website to create a private DNS for me to block ads, trakcers etc, and I'm using it on my tablet and 1 phone and on my 2 phone I'm not using it. So in my case all I had to do is go to phone settings > DNS > Change from Private DNS (maybe even with Automatic DNS there is a problem) Change from Private DNS to Off > Restart your phone or just wait a bit and Done, now Flow will connect with no issues at all! After you connected your flows, you can switch back to Private DNS or Automatic whatever you used before.

I had this problem after having to do a factory reset on my mobile due to an unrelated issue. I reinstalled Opera for Android, but Flow on the app would no longer connect with Flow on Opera 89 of my Windows desktop.

I rolled back to Opera 85. Flow then connected between both devices as normal. A few hours later I was alerted to the Opera 89 update. I installed it and the Flow connection remained in place. No further problems since.

So I went to https://blogs.opera.com/desktop/2022/04/opera-85-0-4341-60-stable-update/ and clicked the Download Now button with the little Windows logo (I'm running Win 10).

I promise you, it won't even take hours. Once you install this update, you will instantly get the confirmation instructions for the two numbers, and your My Flow will be off and running!
Shut down all running Opera windows first, naturally.

I found a solution th the problem described by OP.
When your phone is on the "Follow thee instructions on other device" screen, just press the "Overview"(switching apps) button and force-close Opera. When you relaunch opera on your phone, flow should be already connected.
It worked for me, it may not work for you, but i'm trying to help as much as i can.

Can't do this with more then 1 PC. On 1 PC it worked great, but on second - just log-out right after scanning the code.