How to single out groups, visually within a project and will jpg textures make me loose faces in monochrome or not?

Hello I have about 7000 groups in this project. I know it’s mad (my bad)
but that is what it is after 2 years on it and I am at the end of the build now.

So I am trying to check everything before taking it to UE my next hurdle.
And yes sadly (NO datasmith with SKU 2019)

How can I call out one group or several groups (as seen in the outlines)
and ONLY see that group to give it a name?

I see tiny dotted line in the model but it is so intricate that I would need to zoom into each.
The model is very deep underground.

It’s for a game I am trying to create

Thank you.

Also one more question:
If I view it all in monochrome mode can I save it like that
and will all the many jpg textures remain as plane faces or will they be eliminated?
Thank you so much