If you don't have an idea of a specific build, I'd recommend putting points into reflexes and then one of the other supporting attributes (intelligence or cool) depending on how you want to play. That'll set you up with a basic gunslinger build that you could change to bladed melee later.
Reflexes houses the Assault (boosts assault rifles, sniper rifles and SMGs), Handguns (boosts pistols and revolvers), and Blades (boosts bladed melee weapons) trees. By putting points into reflexes, you can focus on one weapon type and then reset the points later - you could start by playing a katana build, but if you decide you hate it, you can spend the 100k to reset and spec into rifles instead. I just think Reflexes is the most versatile attribute for weapon choice. The Annihilation tree under the Body attribute boosts shotguns and LMGs, but if you spec into that and don't like it, the only thing you can really switch to is the Street Brawler tree which focuses on blunt melee weapons - not as versatile.
As for the supporting attribute (intelligence vs. cool), that's more personal preference. I'm playing a stealth build and really enjoy it, but I've also always enjoyed the stealth aspect of games. Intelligence is for your hacking abilities - think Watch Dogs-esque world manipulation. Intelligence is my lowest attribute at only 4 points (I'm only 2 levels off max level and don't see that changing). But I find that even the base cyberdeck you get (the module that determines how much RAM you have - your "currency" for hacking - and what basic quickhack abilities you have) is perfectly sufficient. I've never found a need to put points into Intelligence as my hacking is more just a tool to supplement my stealth approach. You can, from what I hear anyway, eventually get very very powerful hacks that will spread between enemies and kill them extremely quickly - sounds like you wouldn't even need a gun at some points. I plan on my next playthrough focusing on hacking more, but it's not the kind of thing I think you really need to invest points into if you're not centering your build around it.
I currently have 6 Body, 20 Reflexes, 19 Technical Ability, 4 Intelligence, and 18 Cool. Reflexes for the Blades tree, Technical for the Crafting tree (lets you upgrade weapons to a higher tier, although it's apparently quite a rabbit hole if you really focus on it according to
@robot zombie), and Cool for the Stealth and Cold Blood trees. I'm using the unique Witcher 3-inspired Katana that you get by purchasing the game that I've upgraded to legendary tier, and then I have a unique revolver and a unique silenced sniper as backup weapons. I don't really have any trouble on the hardest difficulty unless I'm just charging head on at a group of 5 or 6 enemies with a katana in my hand. I get basically two-shotted so I have to plan things out a bit (and if I can thin the herd of enemies with stealth takedowns then that makes things easier too), but I definitely wouldn't say I'm not strong enough.
No shock here 
