Last year I was trying to find something to play daily, since I ditched Destiny a few years ago. Then I decided to try Warframe, I got 90h on it, even tho I know it's very little I think I can have an opinion already.
I got overwhelmed by how hard the game tries to make me spend money, I might be exaggerating but I think literally everything has a way to be boosted or achieved by paying. This kind of completely kills that friendly competitive aspect of the game like you achieve something and you just can't tell if it was legit or someone paid for it.
For example I remember there was this double resources boost and other kind of boosts that double many things you do in the game, and I kind of felt bad thinking "fuck man... look how much I farmed here, if I had paid for it, it'd be double", which often was letting me down.
Then suddenly they show that daily offer, I got a 75% OFF offer on game currency and FOMO syndrome just hit, I bought it. I asked on Reddit sub if it's worth it and everybody was just saying they pray to get offers like that, then I thought: well, it seems good I'll do it.
And I did it, now I see how manipulated I got by this game. I didn't spend too much, a 75% OFF was like an old game price, I thought it was fair to pay a game price for playing the game, at least once.
But then I realized if I kept doing it I'd lost myself and always want more. Then I just decided to ditch this game as well before it was too late. The game looks good overall but man... What an aggressive monetization, it's definitely not just cosmetics, you pay to speed up things and way more stuff than cosmetic.
I know that late game you'll eventually farm cosmetics and earn many stuff that at first is bought only by real money, but that's a massive almost inhuman grind to achieve we're talking like 1000-5000h. And then at the end you think again "fuck... I should've payed for a few stuff, I'd have double of everything now".
I mean I don't get it, this game isn't all of this, it feels everything you do in the game there's a part on the screen screaming "LOOK AT HERE IF YOU PAY YOU CAN GET IT EASIER AND WITH EXTRA STUFF WHAT ARE YOU WAITING FOR?".
I fell for it once and now I see how I was manipulated, Warframe somehow helped me on my decision to not spend a cent on extra content anymore. Btw I didn't spend any of my game currency I bought with real money, I just made a mistake and cut it right away.
Been a while since I played, but I didn't even reach 1k hours and was trading stuff much earlier than that. In 850h I think I bought plat once, and made it to 21 (iirc) mastery total, with a dozen or two frames and weapons in store. The only thing I spent plat on is either intermediate currency for trading, or more slots (which you still get plenty of for free from events and such).
The game involves a lot of grinding to begin with, but you can easily farm a bit to find something to sell for plat.
Also Reddit misled you a bit. The game throws 50 and 75% off plat fairly regularly at you.
Especially about the competitive thing though: I've never had that thought. I've never seen it as competitive to begin with, even in a friendly way. And afaict, there's nothing you could do with money that would give you too much of an advantage. Maybe skip a bit of the grind, but a lot comes from mastery levels, build synergies, and knowing how to play your frame right... And even then outside of Steel Path and other endgame-ish content you can easily nuke an entire level with minimal effort.
All that said: yeah, it's a free to play game and it has a few features that will make you want to spend money. You can absolutely not spend a single cent and achieve whatever you want though, which is why people praise it. It just means playing the game more, so the question really becomes whether you enjoy the gameplay loop to begin with and how much time you're willing to spend.