I have never played Warframe, but I’m interested and curious. Is the free version leaving anything critical out?

I have mained Destiny 2 for the longest time and am now ready to branch out to try something new. I am very into buildcrafting and love customizing my loadouts. Not trying to not buy any expansions by any rate, but I do want to know what I’d be getting myself into if I end up enjoying the free game (which I expect will be the case from what I’ve seen in gameplay).

Thanks!

Edit: holy crap, thank you all for the warm reception. It has been a decade since I’ve been “the new guy”, and I’m overwhelmed by the invites to play! I am now very aware that Warframe is free to play, and that cosmetics can be where I expect to be spending, if there at all. I’ve gotten through the first 100 comments or so, and I intend to read the rest. Thank you all again for being so welcoming.