Cabling DSL arrival/ethernet cables - need assistance

Hi Guys,

I would like to move some servers/switch and internet box to the basement where my phone line/DSL arrives.

I open this old "box" and discovered this wiring. I would like to have an ethernet cable getting out of this and going to my dsl box and then from my dsl to the ground floor.

I think the middle cable is a simple ethernet cable.

https://imgur.com/a/rYm1mri

My questions are can I manipulate these cables directly?

the cable from the middle exit this box and ends with a female ethernet socket on the ground floor.

If I cut the cable in two add two male ethernet connectors and wire it as a mal will it work?

Thanks for your help!