Cyberpunk 2077 - Ultimate Beginners Guide, Tips & Tricks! NEW Features & Secrets Phantom Liberty

Is this free on ps4?

Is the relic skill tree tied with the DLC?

You can actually use an old save, you just had to have beaten the last mission and selected one more gig. Song bird will call you.
Edit: I know this because that's what I did after looking it up.
You've gotta get one of the endings, otherwise they won't call you on an existing game prior to the dlc. So beat game with existing character>play dlc with said existing character.

It's beneficial to try and buy cyberware early, cause if you wait till later everything is super expensive as they only sell tier 5 legendary cyberware after a certain point and a lot of the time it isn't that much better then the lower tier stuff.