I'd try watering more (I've read that the soil should NOT dry out completely between waterings. Water when the top half inch is dry) and misting in the morning with a spray bottle to keep high humidity.

Alternatively, if you don't have a spray bottle, place it on top of a pebble-filled tray and fill the tray with water (but not enough to reach the bottom of the pot!).

Ferns generally don't like direct sun, either, and do well sitting 3 ft away from a north-facing window, or in the diffused light of an east-facing window.

This is a Fluffy Ruffle Fern (Nephrolepis exaltata 'Fluffy Ruffles'). I have had mine for over 6 months now and I had the same issue. I keep all of my ferns in a very consistent environment and this plant seemed very happy, but once the new growth got to a certain size the ends would start to brown. One day I was pruning it (I press them after pruning) and I noticed a tiny green caterpillar at the base of a stem. After some research, I found out that it was a Florida Fern Caterpillar. I then checked all of my ferns, and there were at least 2 on each one. It looks like something has been munching on your plant as well, so I would check thoroughly for those little buggers. It is very tedious and they are difficult to find. The smaller ones are green and the bigger ones are black. Here's an article with more info on them

https://mrec.ifas.ufl.edu/lso/entomol/ncstate/cater9.htm

You can get relief by spraying each fern, when purchased and in mid-June, with a product that contains Bacillus thuringiensis (B.t.). This product is specific for caterpillar control and is considered very safe. Good luck!

And what better place for distribution of the caterpillars than a fern farm (lol).