I'm not sure why, I have no cap on my internet and in the past have downloaded everything from the original CCC without issue. The files have stalled at the screenshot shown above this is the 5TH  time  this has happened.  The Assistant gives you ZERO feedback. and because there is NO DOWNLOAD manager your stuck with this. Please take this new software seriously and spend some time making this work for ALL, not just those with with good internet. I install all sorts of software both at home and at work... this has never happened. 
 

Yeah!

Pretty much the same story here.
No progress bar, but eventually it switched to the install button (for other available downloads).

I closed BA (menu) and CbB launched fine. 24.04.1 Build 28

Installed and running fine here.

Cactus Music
...
 
SO I thought I'd try installing directly as someone else said had worked. 
Here is the Bandlab download folder, sort of hidden just like CCC was but somebody managed to dig it out. You can see there is the 2 files for the update. I did not want or need any instruments but looks like you have no choice. 

When I click to run the cakewalk.exe as Admin I get this

So I delete the file and try again. 
 
Just goes round and round. 
 
This is even more interesting as you can see the file sizes are totally different, THis was what was waiting for me after dinner after 8 hours. 

 

My installation is working OK. My files are in these folders (different folders from you):
 

(Image link)
 
 The top 2 are the original install download files to my PC from a couple of weeks ago, so you can see the file sizes. The assistant file below is just 2 days ago.

To access the AppData folder (and beyond) we need to tick or check Show hidden items:
 

(Image link)
 
To get my install to work, I went to Control Panel - Programs and Features and noticed that there were 2 BandLab Assistants listed / installed. I can't remember exactly, but I uninstalled the oldest one, or both of them.
Then I installed and/ or ran the Assistant again and it worked OK.
You could try to do these things. 

Installed fine on my desktop and surface from two different locations. 

Here are the installed core Cakewalk programs from my perspective:
 

(image link)
 
Here's the Cakewalk version. (I removed the serial number for privacy)

(image link)

Downloaded and installed without any problems. 

No problems here, decided to download the newer version of Bandlab as against updating it. Then downloading and installing Cakewalk was, well ........ a piece of cake.

However, the Assistant does need a progress bar or summat.

Jerry

Cactus Music have you actually tried downloading the files on all of your ''3 Desktops and 3 Laptops W7 and W10 '' .
If you still don't see the downloads via appdata/roaming etc then maybe try another computer at a different location and transfer the files as I mentioned.
Not the ideal thing but worth a try.

In the name of research (and for fun) I just did the following:
 

1. Uninstalled all Cakewalk apps and the BandLab Assistant.
2. Downloaded the BandLab Assistant from the website (Get Early Access Now) and installed it.
3. Logged into the BandLab Assistant and chose the Apps tab - Cakewalk - Install button. (I happened to already be logged into my Cakewalk account online via my default web browser.)
4. When asked, I chose to include the extra apps (apart from the theme editor).
5. They all installed OK within about 15 minutes (and I gave them permission to install within Windows when asked by Windows at that time). The Assistant showed the install progression as expected. 
6. However. I could see that the install had finished, however the Assistant was still showing the Install button (not the Open button).
7. I ran Cakewalk (from Windows) and it ran with no problems.
8. I rebooted the PC and sure enough the BandLab Assistant was then showing the Open button (instead of the Install button)

This all took about 15 minutes (including downloads).

What I learned from this (in my amateur opinion) is that maybe the Assistant or Cakewalk could require a system restart upon the Cakewalk install completion. This then resets the Assistant to show the Open button instead of the Install button.
I wonder if a few users here have actually installed Cakewalk correctly (steps 1 - 6) but assumed that it failed based on the Assistant not updating without a reboot.
 
Anyway, a quick 2 cents.