I've rehabbed a lot of properties with plaster walls. What I would do here is cut this so it's somewhat of an even rectangle with a stud at each end. Remove the lath strips. Cut a sheet of drywall thick enough to come close to the finished wall without sticking out and hang it up. Depending on the wall/thickness, you may be able to keep the lath strips in there or use them to bump out the drywall to meet the wall.

Tape up the joints with fiberglass tape. There's a plaster/joint compound called "one pass wall repair" that does really well with plaster. Use very small batches as it sets up fast. Use that to blend/skimcoat the new drywall. You can get away with drywall mud, but the one pass blends better. Let it set, wait a day, sand it out, repeat until it looks good, paint.

I've hung 2 TVs in my house with only one stud and just used heavy duty toggles the rest of the way across without issue.

TVs are a lot lighter nowadays. As long as you have a good quality mount, a good hold on a stud and support across the mounting bracket I think you will be okay.

The whole book I was thinking of how awesome it would be to see a TV adaptation on the scale of Game of Thrones or similar.

So many great pieces of art have borrowed from this book. I think it could really be something special if done right.

It was a bucket list read for me that I finally checked off this year.

It's crazy how many times my jaw would drop, or I'd audibly say "oh shit", or even have to push back a few tears in places, all from a book that's nearly 200 years old. It's an absolute masterpiece in storytelling and how pull off a slow burn. It's a long read, but so worth it, and I really wish I'd picked it up sooner.

Agreed. It would make a great miniseries. It'd be a 4+ hour movie and would still be super condensed to get it right.

Give it a good budget and 10-12 episodes and I think it could be really special.

I helped a buddy with a similar issue recently. I picked up some 1x6 planks, ripped them to the depth of the opening, and used them to cover the exposed 2x4's. Then I just put new trim around the doorway, putty/caulk/paint to finish. Came out looking really nice, and was less than $100 in materials to knock out.