Melee is absolutely not needed, disregard that advice.
Let's see...I finished my second Very Hard run not that long ago, so here's what I'd say is important to know:
-You get to pick three attributes to max out in the base game, four in the DLC (plus a DLC attribute minitree that is free to max if you explore). This means you end up very omnicompetent over time and there isn't a lot of need to sweat the synergies. THAT SAID...
-Some trees are 'primaries' you focus on and spend your cyberware to boost, some trees splash. Generally speaking, every tree has one splashable branch out of three, one branch that may or may not be splashable depending on build, and one branch that is the 'I want to do THIS thing primarily' focus, which is the left-side branch. Intelligence can splash its left side with a weapon spec from another tree (which are the left side branches too), but it's the only one where you can get away with that. Why does this matter? Well...
-Three of the trees get an Operating System cyberware that DRASTICALLY changes your playstyle and what you can do, and I would urge you to think about what's more your jam before you go in. They are Body, Intelligence and Reflexes. Body's Berserk lets you become an unstoppable melee murderbeast and eventually straight up makes you invulnerable while it lasts at cost of not being able to use ranged weapons, Intelligence gives you hacking powers, and Reflexes gives you Sandevistan, AKA superspeed that works like a bullet time (and also has number buffs on top). If any of these sound like they fit into what you want to do, consider focusing on the appropriate tree to make them stronger because the payoff is noticeable. There's a fourth path available which is 'no OS, just give me a lot of extra cyberware points for elsewhere' but it's an advanced setup and I really don't recommend it while starting out.
-Everything is viable so there is no need to worry about things beyond making sure you pick an OS that matches your main spec (ie don't be a goofy goober and focus on hacking then get sandevistan or berserk for example). I personally feel Tech is an amazing tree to jam into any build but every single stat combination will produce amazing results, and having used every tree, I promise they all transform your experience if you pump them up and they are insanely fun to play with.
-If you like to play on hard or very hard modes, work on gradually acquiring 100% Mitigation Chance (and boost the Mit Strength). This is the only requirement the game asks of you as you crank up the difficulty.
-Unlike most open world games, Cyberpunk's critical path is actually interesting, cinematic and compelling. The way I've described it since 2.0 update dropped is that it's three excellent games jammed together (a breakneck speed FPS, an open world game and a linear RPG with involved sidequests) that become something more than the sum of their parts. It is completely valid to mainline the story for a long chunk of time if you want and you won't be let down, unlike a Skyrim or the like. That said, exploring is very fun, so don't sleep on it!
-Barring some very specific gimmicky builds (and LMGs, which have to wait until the DLC to get iconics iirc), your weapons will eventually be Iconics that have unique and powerful effects. To name one example, the very first iconic weapon you get, the Dying Night, is a mean old bastard of a pistol that electroshocks enemies if you hit them enough times in a row for huge damage, and its impact is very noticeable compared to a generic gun. Make sure to keep disassembling gear you don't need for materials to upgrade your chosen cyberware and Iconics, because every tier is a pretty hefty performance jump!
I think that's everything of note. If you got any questions during play feel free to tag me, I'm happy to explain anything that's uncertain.
Shine on, you crazy diamond.