I think the original Prime Directive from TOS was fairly straightforward. A statement about the U. S.' involvement in the Vietnam war. Another, "In the future, we don't do that kind of stuff anymore." Storytelling in Star Trek evolved and expanded over the years. I think this has left the Prime Directive still valid, but vague.
Vague in the what ifs of not intervening to prevent the destruction of a civilization that isn't brought on by that society's (or societies) decisions. I get if the Federation sits out on stopping a society its own self-destruction. Even if new to warp technology, a planet with societies bent on self-destructing means about all the Federation could do is become the planetary police force. I think SNW's s1e1 planet Kiley 279 is an outlier. Kiley 279 being on the precipice of warp-backed absolute destruction was Starfleet's fault. Unintentional, but still their fault. I think violating the Prime Directive in that situation was warranted.
The Prime Directive is like the rule to stop at red lights. Not an extensive treatise, but important. Violating that rule can lead to very bad things. Still, sometimes following the Prime Directive can lead to very bad things, like in the Terran universe. I wonder what would happen if that scenario was repeated in the regular Star Trek universe. I think the First Contact Protocol is a lot more extensive and comprehensive. There's a lot of possible first contact scenarios, from "hey, cool, welcome!" to panic and attacking the landing party.
The Prime Directive is important. However, I think it isn't comprehensive.