That's good to hear as it means it is something that can be improved! I was wondering if it was the norm or not. Next steps will be talking to nintex as well as Microsoft as our tenant experiences a lot of slowness issues that are experienced inside and outside out network. The tenant issues could be compounding the problem https://tutuapp.uno/ https://showbox.bio/.

I'm not very experienced with nintex online, what banner? The nintex branding banner on their default new forms? That has been removed. 

Anybody from Nintex have a response to this? Very simple form with a few fields takes a very long time to render.

Apologies for the late response.  In general, Forms load time in SPO will naturally increase due to added redirect, response, processing time within the ecosystem, navigating thru MS Add-in app and SharePoint APIs.  Please submit a support case with details such as form type, Task or List form, browser, any custom code, etc. so that we can replicate and then investigate.  For a faster form load time, you may also want to consider the latest from Nintex on Sharepoint Framework app (SPFx) support.