Questions about On-Premises Data Gateway for a On-Premise Dynamics 8 IFD

Please so kind as to read my full post before responding.
Thank you for your consideration.

We have been tasked with checking if it's possible to design a Canvas App for storage managment in a company that has a Dynamics 8, On-Premise, IFD Installation.
I know nothing about On-Premise installations.
I only found the On-Premises Data Gateway via google and know nothing about except for the following linked documentation which does not seem to contain all the information I am seeking.
I am aware of these documentation:
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/gateway-reference
https://docs.microsoft.com/en-us/power-bi/service-gateway-onprem
https://docs.microsoft.com/en-us/azure/analysis-services/analysis-services-gateway
and this download site
https://powerapps.microsoft.com/en-us/downloads/

I am currently writing from a stage where our admin installed the gateway and share it with me.

I haven't yet used it in a canvas app yet and am still collecting my thoughts and questions.

My questions:

Is there some sort of full documentation of that On-Premises Data Gateway?
The documentation I found via google seems to be incomplete and consist either of just a few pages of docs.microsoft.com/forum/blog entries.
None of that looked like it was supposed to be a reference.
After the installation with GatewayInstall.exe the sign in didn't work initially

We got it to work after our Sysadmin turned on Javascript for the Internet explorer.
He doesn't want to keep Javascript turned on for Internet explorer on the Windows server.
Can we turn it off again or does the On-Premises Data Gateway still need Javascript?
Do we need to login to the Windows Server and use Sign-In (this appears to be the only part needing Internet Explorer Javascript) in the Data Gateway again at some point in the future?
The data gateway only cares about the underlying SQL Datasource, i.e. the Dynamics version doesn't matter as long as the Microsoft SQL Server is the same, right?
At least the Docs that I found seem to mention Dynamics almost nowhere, in particular now among the Data Source content.
Do I have to do something special because of the IFD/ADFS deployment?
I couldn't find anything tangible on that.
Does the current iteration of the On-Premises Data Gateway
https://powerapps.microsoft.com/en-us/blog/on-premises-data-gateway-may-2019-update-is-now-available/
only allow Read access, as suggested in this older blog entry
https://www.kingswaysoft.com/blog/2018/11/22/Leveraging-PowerApps-with-Microsoft-Dynamics-On-Premise

This other post however seems to suggest that creation, update, delete are also possible (if (?) those sql actions can be done from connecting those SQL tables in PowerApps via the SQL connector and the On-Premises Data Gateway as well)
http://dynamics365.ie/flow-synch-d365-onprem-database/
The description of how the On-premises data gateway works suggests that there will be traffic using the Azure Service Bus.
Do I need a Azure Service Bus Namespace/subscription to connect PowerApps Canvas App to the On-Premise Dynamics installation?