Tips of large fan leaves twisting?

probably fluctuating pH -- this causes varying growth rates in the leaves, so you get waves/warping etc. the paling of the top leaves are mostly likely something else, but i'd ensure pH is relatively stble (within +/- .2 is probably good goal, and ok to do better than that too). Once thta's stable for a bit, and you can observe new growth after that point -- if it looks fine it was probably related to the pH .. if it continues to reference a leaf chart and make your best guess like anyone else... at the least, paling from in to out on leave is one of the more distinctive symptoms.

She’s still pretty. Don’t cut her hair off! She’s just in her awkward phase. Nah, but seriously, why defoliate her. She needs those leaves to grow. Just get her ph together and let those leaves do some work

looking by your set up looks like a dwc set up and I know from experience ph fluctaions are very common if you want to stop it happening altogether I would look into nutrients that do not require you to balance the ph a lot of feeds are ph neutral with tap water the best by far in my opinion is gen1:11 nutrients.

Can't see anything really wrong. Tip "issues" looks like damage caused by the leaves hitting the edge of the potter, nothing else. Apart from slowing growth, I can't see how defoliating would help in any way.

Yes it's the PH, you can tell because the whole plant is changing to a light green shade. Also check that the RH is good.