It's not necessary to try to finish all of Anking - passing will likely be pretty easy as long as you give reasonable effort during preclinical time, and preclinical material won't likely impact grades later on to a large degree. How much you use anking depends on how much you like anki as your main study tool, and whether you prefer premade or homemade decks. You could then follow a graduated approach taking into consideration which decks work best with anki, your own priorities, and your own study strategies. This means you would only need to keep up with a much smaller proportion of the full deck, if any at all.
1) You do prefer anki as your main study tool, and like premade decks - in this case, you might as well go ahead and use anking since it's the most complete, well-tagged, and well-resourced deck. It works very well if you're on an accelerated curriculum, if your curriculum follows first aid/board prep material very closely, or if your assessments are mostly NBME/multiple choice based. As you receive lectures, just unsuspend relevant chunks of cards from the core zanki decks (pharm, pathoma, costanzo, maybe B&B) while ignoring some of the supplementary additions that don't really show up in classes (BG uworld adds, other random cards). You would just keep up with your cards as long as you are in the relevant block, and stop using them afterwards. Even though you'd likely forget a good bit, you'd certainly lay the scaffolding to do enough to pass step and set yourself up for clerkship year. While it's certainly not necessary to use anking for your classes, some people enjoy the workflow and focus compared to just staring at or annotating lecture slides, or the tedium of making anki cards yourself.
If you're neurotic about making dedicated extra chill/easy, or about setting yourself up for clerkship year with a slightly better foundation, there are a few decks that you might consider keeping up reviews even after the block is over, into dedicated. In order of importance:
A) sketchy micro deck
B) sketchy pharm deck
C) pixorize/sketchy biochem (mostly diseases; maybe the pathways)
D) Pathoma 1-3
E) Rest of pathoma
F) Biostats
All of these subjects work very well with anki style memorization, especially when used alongside visual resources like sketchy/pixorize. Subjects not mentioned (e.g. physio) or lower ranked don't work as well with anki, or can be more easily brushed up on during dedicated periods without having to brute force memorize. Depending on how worried you are and how much extra time you have, you could just do A) and B), or just A), or any number of selected resources. Again, this certainly wouldn't be essential, but might save you a little bit of time in dedicated and let the info really soak in so you don't forget it in the future.
2) You prefer anki as your main study tool, and like making your own cards - mostly ignore anking. If you're neurotic, you could try keeping up with a subset of of the deck in accordance with the rankings from 1).
3) You don't like anki - ignore anking. Again, you could consider using the ranking in 1) to keep up with a small subset of cards totaling <10k, but you could also likely do just fine without.