After Communication Site upgrade of the root site full-width sections are limited

[Finnair]

If you upgrade root site's team site template with a communication site template, the new home page (front page) contains one section that can have a full-width web part and it's the first section (uppermost). You cannot add a full-width section down on the page because it's not available in Add Section menu.

Is there a possibility somehow to allow full-width sections also on other slots on the new homepage?

The upgrade was done with Powershell: Enable-SPOComm... and it was otherwise successful.

[#2]

I would recommend you to create a new Communication site and do a site swap instead with the root site. It's alot easier especially when it bugs like this.

[#3]

Related to that, I've found after creating a brand new communications site, I cannot add the right justified column anywhere on page. I tried deleting the Hero webpart in top section, deleting the top section and it was also not available in any other section both prebuilt or newly added. Is that expected behavior? Did the system generated template change recently?

[#4]

Sounds like a bug but hard to know without see what you are doing...,
Try with a different browser and see if you get the same result. Remember to delete all full width sections