If you want to go fast, do your new radicals as soon as they’re available. The same hour, if possible. Guru them as fast as possible, then do new kanji reviews right away. Vocab you can do at your own pace. Of course, that’s all if you want to go fast. Which you don’t have to. Going fast means more reviews per day. For me, going as fast as possible has always been good for motivating me, but for a lot of people, going faster isn’t worth the extra reviews.
I would recommend doing the 0/0 Challenge, which is a challenge to get both reviews and lessons to 0 at least once each level. It’s not required or anything, but it’s a good motivator to keep things under control, especially if you want to go fast.
I also have aphantasia, and so I usually made up my own mnemonics for kanji. It takes a bit of time to figure out what works for you, for me it was particularly helpful to recognize when certain radicals appear in a lot of kanji with the same reading (for example, 販, 坂, 版, 飯, and板 are all read はん). As for actual mnemonics, I benefited from simpler ones, the simpler the better. Feel no need to actually use the names of the radicals present if it isn’t helping you.
I definitely noticed it getting easier. It takes time to learn how to learn, but once WK is part of the routine, it becomes pretty easy and natural to put more and more time into it, and reviews go by much faster. I’m currently redoing WK, but when I did it the first time, my time on level steadily decreased, and my accuracy didn’t degrade at all as I got into the upper levels. Good luck! I hope you find WK helpful! Feel free to ask the community any questions you have <3