Could the rubber brake lines cause this issue

Your brake lines could be spongy but I suspect a bad master cylinder and more. I would probably replace the master, both front calipers and bleed out the whole system.

and don't get all upset when the shop charges you for brake fluid that you already have ( or had). I am fortunate to have a shop that I go to that allows me to bring in my own fluid and parts. BUT they won't guarantee the work. That's fine with me since the car is over 10 years old and I get full insurance coverage with my provider.