Open a specific page or pages broken since KB4023057 / KB5003173 (only works if you set Bing as the default search engine).....

Just checked my workstation and it is the same Edge version, and the same windows updates to KB4023057/KB5003173). However, on my workstation everything is working as expected. That said, on the laptop that has the issues I do have the taskbar 'News and interests' option available (Dell XPS 13 9370). Not sure if that is relevant or not?

Good point, though I deleted the gif now... Will redo it later.

Does Edge open into the new profile?   Yes

Does it open with the start page you selected at (3)?   No 

If you search from the address bar, are you taken to a results page with your preferred search provider? Yes (it goes to DuckDuckGo)

A.Settings > System > Start-up boostAlready off

B.  Settings > System > Continue running background apps when Microsoft Edge is closedTurned off

C.  Settings > New Tab Page > Preload the new tab page for a faster experienceTurned off

Nope, even with reboots and trying all combinations nothing changed - the new profile still comes up with new tab page

Edit: And just to confirm - as soon as I set the default search engine to Bing the user defined start up page comes up as selected (on the new profile)

Great!

[Aside 1: It might have helped somehow to indicate start and finish in the video, because these GIFs loop continuously and it can be difficult to see what precedes what. In the ScreentoGif editor, I can select the first frame and then under Image add a title frame. With a vividly contrasting background colour and a longer duration, it shows clearly where the loop starts. Aside 2:I hope this doesn't divert you from whatever you're supposed to be doing this weekend. I'm really hoping you'll suddenly cry Bingo! at some stage, but I'm quite prepared for disappointment.] 

The Edge team - like me - have not been able to reproduce this fault, so they've asked to check whether this occurs with all profiles. I've been trying to find a reasonably simple way of doing this, and this is the best I can do ATM:

1. Launch Edge, then click on the profile picture and select Add profile. Unless you want to, there's no need to sign in.
2. Give the profile a meaningful name; you could also select one of the inspiring display pictures for ease of identification.
3. Configure the search provider and start-up page.
4. Find the folder name of the new profile: in a new tab, open edge://version. The folder name is the last item on the line labelled Profile path. It will probably be Profile 1. Close down Edge.
5. [I'm assuming you don't use the start screen, just the menu - like me. These operations are all reversible.]
   Right-click on the taskbar icon, then right-click on Microsoft Edge and select Pin to start.
6. Press Winkey to reveal the start screen with its new tile, then right-click on it and select More > Open file locationThis should take you to C:\ProgramData\Microsoft\Windows\Start Menu\Programs with the file Microsoft Edge.lnk selected.
7. Right-click on this file and select Properties. In the Target box, click at the end of the path, then type a single space and two hyphens, then profile-directory="Profile 1" or whatever you discovered at (4) above. The target should look something like this:

   	"C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe" --profile-directory="Profile 1"

8. Click Apply and OK, then return to the start screen and click on the new Edge tile.

Does Edge open into the new profile?

Does it open with the start page you selected at (3)?

If you search from the address bar, are you taken to a results page with your preferred search provider?

If you still see the same behaviour (the browser launches with the NTP instead of your chosen page), here are a couple more settings to turn Off if they're On:

A.Settings > System > Start-up boost

B.  Settings > System > Continue running background apps when Microsoft Edge is closed

C.  Settings > New Tab Page > Preload the new tab page for a faster experience

For really rigorous testing, bearing in mind the last remarks in my Aside 2above, you should try every combination of these three settings, i.e. all off, only A on, only B on, only C on, A+B, A+C, B+C, A+B+C. Because they're System settings, you should restart the computer after each setting change, then use the start screen tile to launch the browser.

Over to you!

Managed to create an animated gif.......

Thanks Noel, much appreciated. Feedback sent.