While I agree almost completely with what @jneapan has mentioned, I feel that you can’t ignore your base knowledge of kanji completely.
Before WK I learned a bit of grammar (I was somewhere between N5 and N4 level). I also knew a bit of kanji (like a 100, maybe), but not very well. Back then I did try to read manga but it was really frustrating to have to look up so many kanji. I’d sometimes run into 4-kanji compounds and it took forever to look them up just to figure a single word in sentence. Sometimes by the time I finished looking up all kanji and the words in a sentence, I had forgotten half of the ones I looked up at the start of the sentence.
After WK things went way better. Personally I started seriously trying to read manga at around level 20, and I felt I made better progress (I had also learned a lot more grammar by then). Even if I didn’t know a word, knowing how to pronounce the kanji in it helped me look it up way faster than trying to search by radicals (not to mention when I tried drawing kanji). However, like it has been mentioned, I don’t think it is easy to point at a specific WK level and say “you’ll be fine at this point”. You will often run into kanji that are not even in WK (specially in names of places and characters, though thankfully most manga gives you furigana for those).
That being said, I cannot stress enough that grammar is more important. Looking up a grammar point can be incredibly tricky, and sometimes when you find an explanation, you discover that it is based off some other previous grammar you don’t know either, making you go down a long rabbit hole just to figure out a single sentence. That’s happened to me a lot.
Another piece of advice is to use the jitai extension , to get used to weirder fonts. Sadly manga authors love using these scribbles that looks like they are made out of squashed ants to write some side comments that characters make or for sounds effects here and there, and they are a big headache to figure out sometimes. It took me like 10 minutes to figure out what on earth this was, even though I know the two kanji in it by heart.
Anyway, my advice is: try to find a manga you are interested in that seems to be relatively simple, and give it a try at your current level. As you go you will start to see more clearly if your weak point is in the grammar or in the kanji department. If it gets too frustrating, it is probably better to stop and focus a bit more on studying more Kanji and the grammar points that may be giving you trouble. Patience and determination will definitely be necessary.