Which installation cable for ancient conduits?

Hello, in my parents' house, the telephone cables from the attic to three rooms are laid in conduits dating back to 1962. I would like to replace them with Cat6 or Cat7 cables, preferably duplex, so that the router/switch can be positioned flexibly. Do you have any recommendations for which cable type would be easiest…

Laying fiber optic cables outdoors with or without ductwork?

Greetings to the experts out there! I'm currently working on a project to connect an outbuilding to my house via fiber optic cable. I have to lay about 105 meters of cable underground. The question now is: Should I lay the entire length of the cable in a separate conduit? Or is it sufficient, if…