If you search YouTube for V60 brewing videos and guides you’ll find about three billion different ones. Some with agitation, some without; pouring fast, in the middle, making circles; 40-60 or 30-70 or whatnot.
I always think to myself that they’re mostly just fluff.
It all depends on grind size and temperature. Doesn’t matter how you pour (well, within limits I would think) as long as you get your temps and grind right for the pouring technique you’ve chosen.
Admittedly, I haven’t tried a ton of different ones, maybe three or four. But this is the feeling what I’ve got.
Maybe there are some edge cases, like Ethiopian coffees being more prone to clogging the filter so less agitation might be a good idea.
Upgrading grinder can definitely help with fines, and btw manual grinders usually give you way value for your money. Also some coffees do make more fines than other ones, like I mentioned in the post that Ethiopian coffee tends to make more fines.