Tl;dr: Discovered poker in mid-2020, became obsessed with it, wanted to be a pro and play tournaments against the best, started in the micro-stakes of course, year and a half later I'm still there. I played £2 cash game buy-ins and £1.10 tournament buy-ins and lost about £70 overall. This might not seem like much but to try so hard and play for so long and STILL be in the micros is the main problem.

What should I do? I want to try again but I just can't move up.

I think it's pretty normal for it to take several years to go from a complete beginner to a winning player and only if you study and practice.
Poker is much harder than people think it is.

Just being better than everyone else at the table isn't enough. You also need to beat the rake, which is huge.

How can you be seriously thinking about wanting to be a pro poker player if you've never experienced anything close to it?
Should this really be your objective?
How can you know you want something if you don't understand the very thing you claim to want?

How many hands have you played total?

That's the thing, the IDEA of being a pro sounds amazing but I'm not sure if I would actually want to when it comes to it. I love the game but I'm just terrible at it so far. I don't know how many hands I've played because I spread it out across online websites, PokerStars and BetFair. I have a HUD (Poker Co-Pilot) but my computer broke and I lost all the data. My current incarnation of Poker Co-Pilot has about 20k hands on it but that'll be just a fraction of the real total.

It's hard to really enjoy something you're "terrible" at.
I doubt you're that bad though.

Get some coaching and/or join a training site.
Don't be so hard on yourself, poker is hard.

The real question is what you're doing to improve.

Putting in volume without doing off-table work or study to improve will just lead to spinning your wheels getting nowhere. Whether it's engagement on 2p2/strategy groups, joining a training site and seriously watching the content (this means taking notes, perhaps rewatching vids, etc etc), reading some of the better modern poker books (play optimal poker, modern poker theory for example) or paying for private coaching is kinda up to you, but you have to do something to push forward.

Playing hands is not enough to improve - practice makes permanent, not perfect.

If I wrote something like the following, what would you think:

“I just discovered baseball and I really love it. I decided to start playing baseball in mid 2020 with the goal of eventually becoming a major League player. I’m getting pretty frustrated, though. I’ve been playing in a rec league at my local park and I don’t seem to be able to do well enough to reach even the lowest level of the minor leagues. It’s really frustrating; I think I should at least have gotten into AA by now!”

Everyone thinks becoming a poker pro is something that just anyone can do. We don’t watch an MLB game or an NBA game and think “Gee, I could be a pro baseball player or a pro basketball player”, but for some reason there seem to be a lot of people who watch the final table of the main event or a WPT event and think “I can do that too”. Well, maybe some of those people are right, but most are not. It takes talent, work, and dedication to reach the top level of poker, just as it does for other pursuits.

Full disclosure — I’m not a pro; I never will be a pro. I just recognize how hard it really is, and I content myself with playing micros as a rec with a relatively modest win rate: that’s probably my ceiling as a poker player. Micros may well be your ceiling too, and that’s okay; that’s the ceiling for a lot of players.

I do believe making a living playing poker is considerably easier than becoming a professional baseball player or most any other athlete.
As a pro athlete you need to be one of the best in the world.
As a pro poker player you just need to be better than the 5-9 people you're playing against.
It's still hard and tons of work, but not really comparable to athletes.

I do like the analogy though. Just not 100% accurate.

Yeah, the nice thing about poker is you can make a living being in the top ~5-10% of the playerbase as long as you game select even a little bit. With pro sports, you have to be in the top .01% to have any kind of shot. With that said, the concept is similar.

And although it's nowhere near as brutal as pro sports (except for maybe the super highstakes online scene), it still takes plenty of time and effort to pull yourself up from beginner level into that top ~5-10%. If you aren't actively developing your game and are just putting in hands, it's not really going to pull you up the ranks naturally. You need to do things to actively improve if you want to climb relative to the field.