Why are my GMail Sub-Folders empty on iOS device

i have used my main office PC as my main point of work since 2017 and use iOS devices (mainly iPad) when I am out of office. I use Gmail and have it synced to all of my devices which has worked well over the years until the latest update to 18.1.0. Now the subfolders on my devices are empty so I deleted the account from my iPad and added it again after restarting but it’s still the same. Pulling my hair out on this one…

[Re-Titled By Moderator]