How to get ethernet working on install for a motherboard using Realtek 8125 2.5Gbps chip?

What?
The package from my repo or your build from source?

The package from your repo.

Ok thanks for the reply.

has anyone tried this now kernel 5.9 has landed?

Try it by yourself.

Add kernel:stable Repo and install kernel from that Repo.

I did just install TW using the iso dated 30/01/2021:

It installed okay - and during the install it appeared to be able to configure the repos okay, but…

When I get into the desktop and open up Firefox it can’t load any webpages - inc the initial suse help/info page.

Checking the taskbar the network widget says it is connected - with an orange symbol - and at most it is transferring 20bytes of data.

Has anyone ever got this working? And did they have to [work] to make it work, or did it ‘just work’?

Two months old at least, Nobody subscribed anymore to the thread, a new TW, result: your question is hidden in darkness.

I think you are better of starting a new thread so that all people that look for new threads do see your question.

And then better do not re port that FF can not connect to HTTP servers (a typical end-user report), but report as system manager about your network connection.