Confusing situation;c Keeping fiber? Or switching to ethernet?

Hi guys, I wonder what would you do in this situation.

I have a server room that has fiber link with 100mbps intending to manage a 600mx200m building with approx 300 concurrent users

I wonder if it would be better to keep running all the archi with fiber of switch it to ethernet with cat6a / cat5e alongside with repeaters to reach an additional 100m whenever needed)

the reasons I'm planning to switch to ethernet are :

-Running with ethernet is a lot cheaper and easier to manage and deal with.

-100mbps can be easily managed with ethernet cables so why bother using fiber for such " low " bandwith.

So what do you guys say .