Ooh, interesting topic! I figure most people here love their cintiqs, but as a non-Wacom/cintiq user I guess I can play devil's advocate a bit.
This will sound weird (and again I can't comment on the quality of cintiqs since I've never used one, though they are considered the industry standard), but I generally use a regular tablet without a screen, which only plugs in with a USB cable. (Huion 610 Pro V2, 10x6.25in work area; it's a bit older now, but it's this one here: https://smile.amazon.com/gp/product/B07DPC98DT/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1)
I did try a tablet with a screen for about a year or two (Ugee HK1560 15.6 In display), and while a Cintiq would probably be much better quality, what I discovered was that I never actually looked at the screen; I would always look at the computer monitor anyway, because my hand blocked half the art when I was looking down. (The monitor was also a bit more finicky in terms of compatibility; a screenless USB plug tablet works mostly like a mouse and mostly all you have to do is plug it in and maybe install a driver, whereas the screen had to be plugged in via USB, plugged into a power source, and also attached via some other port that generally needed me to buy a particular cord to attach, like a mini port or Type-C connection [though that last one could be because I'm on a mac which doesn't have an HDMI port].). The line quality as far as I noticed was about the same as the smaller Huion, though sometimes the Ugee did have more of a tendency to look digitized, though maybe a Cintiq wouldn't do that.
It's possible an artist with more precise control or attention to detail than I have might notice a bigger difference in quality between a cintiq and a cheaper tablet without a screen, but honestly based on my own experience I've tended to kind of advocate for the notion that cintiqs are great, but not the only option. (If you've never tried using a tablet before, it might be worth getting something cheap-ish to start out and just see how you like it. Drawing digitally with a stylus can feel jittery and hard to control for a while until you get used to it, but I personally didn't find this improved much with the screen over without a screen, though I guess I had been using regular tablets for quite a long time at the point I tried it. Although if you've been using a stylus already to work on your phone, I guess maybe it would feel about the same as a tablet.) If you did want to try something cheaper out, the main things I'd look out for is get something big enough, and make certain it has pressure sensitivity; the only Wacom I used was a little small cheaper one (no screen, and a 5.8x3.6 work area) without pressure sensitivity, and the quality jump when I moved to a bigger Huion of the same price was dramatic.
Oh, also size and weight of tablet can be a consideration if you're more comfortable holding it on your lap like a sketchbook, another thing I discovered with the Ugee. Cintiqs are probably a lot more streamlined, but still a consideration in terms of what tablet/screen size to go for. (For my tablets I've found the ten inch more comfortable than the 15 inch, not just in terms of weight, but also time and effort in terms of how far I had to move my hand. But, some artists prefer to be able to make bigger gestures.)
But! Anyway, mostly just wanted to add another perspective, since my experience with tablets has been a bit different from a lot of people.
.
Clip Studio is a great program, I used to use it (well, my version was technically Manga Studio) quite a bit for inking because it has some great brush stabilizer options, and also some really amazing ruler tools. (I use mostly Photoshop these days, but Photoshop completely lacks brush stabilizers and rulers both without additional plugins, or any vector options.) Considering one of the biggest issues most people have trying to use a tablet for the first time is the tendency toward shaky lines, the stabilizer is particularly useful.
