sure, i ended up writing a ton of things, but cut most of it down to be as concise as i could (i'm really bad at it), we should talk in a chat or VC about it one of these days ^^
basically, to me, player character death is something you need to yield very carefully in most games because it inspires deep frustration, but especially in ttrpgs there's a bunch more reasons to avoid it the majority of time
imho combat should not in general pose the risk of death to the players, it only really works as a general omnipresent threat in specific game styles and settings, and otherwise can work in specific situations where you want to raise the stakes dramatically (like BBEG reveals and the more important boss battles), but even then you can achieve the same effect with better tools
this comes from some very basic game design principles, namely the golden rule of working from feelings first (both that you want to impress and want to avoid impressing), and build experiences for it, not the other way around. and frustration is a feeling you generally want to yield carefully and avoid impressing most of the time
then the other issue is that it really goes against the strengths of most ttrpgs we're used to, and in particular D&D 5e is not tuned for it
it's not impossible, you can do it, it can work, but it will be wonky, and more often than not will get stale pretty quick. to me if you take that as a basic rule of running games, you'll miss out on most styles of play and most enjoyable experiences
to give one more practical example, you can't have a gung-ho adventure where players are free to bullshit their way into and out of situations well above their heads if you intend to punish players for not being diligent and prepared. going into things unprepared and without diligence is the fun in these games
i mentioned blades in the dark because i believe the way it handles heavy omnipresent risk is so good it's a great case study - they even found ways to make the style i just described compatible with having heavy risk all the time, but it takes a lot of game-mechanical ingenuity and design focus to achieve it. you should read it!