Throwing in my two cents - great advice here. Bottom line - It will be hard, no matter how much you’ve studied, but it will get better. Real language experiences aren’t really graded to your level - there’s going to be grammar you don’t know because it’s N1 and not in your current textbooks, but is actually used a fair bit (or the author you’re reading uses it a lot). There will be tons of vocabulary to pick up. A few things that have helped me:
Reading long-ish manga series’ - it definitely gets easier the more of that same story you read - you get used to the writer’s style, and you tend to see vocabulary repeated.
Reading lots - In principle I like Tadoku, but the material I want to read is a bit too far above my level to not look up anything. Personally, I use a bit of hybrid - look up words that I really need to to understand what’s happening, keep a list in my dictionary app - but as much as possible, just keep going and get the gist. Once I’d gotten further into the series I just finished (like, volume 3-4), I went back to my list for chapter 1 to see what words I still didn’t know, and threw them into an SRS. Once they were sticking okay in SRS, I went back to chapter 1 and re-read it. It was certainly easier knowing more of the vocabulary, but I would have progressed at maximum 1 chapter per week if I’d been trying to SRS all the unknown vocabulary before moving on, and that would have annoyed me from the perspective of knowing what happened next. Also, some of those words in my list did not need to be SRS-ed - the more frequent ones I’d usually picked up by the time I came back to the list. Bonus - I can compare the lists and see that the average number of words I needed to look up was declining (but there were still a fair number of them). Wouldn’t work for everyone - you need to really like the source material - but something that I’ve found helpful.
Definitely look for something you’ll like - but I wouldn’t feel confined by things that you’re familiar with in English. I’m not really a big manga reader in English, and don’t have a ton of familiarity with many series at all - I pull a lot of samples from kindle to try for a bit and see if they seem intriguing, impossible to read etc. I collect any interesting looking free volumes so that I can read a volume and see if it’s something I want to read. Just recently finally opened up one of them, my first thought was ‘this is a little unusual’, but I’ve quickly come to ‘this is fun, I want to read more’ - probably wouldn’t have picked it up based on description.
It’s okay to put the book down - if you’re not enjoying the story, if you’re frustrated by how confusing it is, it’s fine to try something else and come back to it later (or not). It feels like you ‘have’ to finish it because it’s studying, or because you went to the effort of importing it, but it’s more important to read something you actually (at least kind of) want to read.
Try a little bit every day - I found that helped most with progress - I will finish 1 page, or even 1 panel, just to stay in routine. On a good day, I read a few chapters of manga (I look a lot of stuff up, my Japanese, to be clear, is not great); on a busy day, I read a panel (or a few if there’s no text in the next available panel) and go to bed.
Join a book club, or read along with an old one, if you feel like the camaraderie and support would help - you may or may not like the book choice, but we have a fair number of old ones so likely you can find something that interests you (or nominate something you’re interested in).
And good luck!!
Even when I arrived at level 60 with Genki 1, reading was too much of a struggle. I suggest to finish Genki 2 as soon as you can. Grammar (and not vocabulary) will make all the difference. You can easily look up words that you don’t know.