Best way to fix hard brake line

I just pulled, cleaned and regreased both sliding caliper bolts on the front drivers wheel but it’s still sticking.

I think I will just buy a brand new non reman front drivers side caliper and install it.

My final question is, when I bleed the brakes do I have to bleed them all or just the one front drivers side line? (That one is the closest one to the master cylinder by the way)