Too much... but take my comment with a grain of salt since I’m not a fan ...

i'd say TOO LATE on shiplap. stick to the accent wall behind your bed , less to remove in 5 years.

Look, I too love Joanna Gaines. But do yourself a favor and avoid falling trap to this trend.

That ship has sailed post some pics of the bedroom and see what pops.

I think one or the other is best. I do like shiplap, it became a trend for a reason. You could also do wallpaper on the wall and shiplap on the ceiling.

Thanks everyone for the quick input. Some of them were funny. I'd post a pic, but honestly it's the most boring bedroom. Ugly as S#$t painter grade paint (think camel color). I guess it falls back on the old saying less is more

The mere mention of "shiplap" triggers houzers into a frenzy. I would do it if you like it. But I live in "Waco".........

If you're set on adding shiplap, I would suggest just putting it on the headboard wall since that is a main focal area and since it will be easier to later remove from a wall than a ceiling.

If you have to ask "is it too much?" Then it probably is. Sorry :(

Here are a variety of wall treatments that can be considered for your bedroom. I do think applying either horizontal or vertical mouldings might be a easier more current application instead of shiplap.

You said it: you have cheaply painted beige walls. Small wonder it’s boring! Go buy yourself some TOL quality paint in a color you love. Then maybe look for a high-end wallpaper for behind your bed. That will be nicer, no more expensive, and you won’t be kicking yourself in a couple years when you have a bunch of boards Liquid Nailed to your sheetrock.

Joanna Gaines throwup is not an appropriate look for the vast majority of homes. You need not be one of the lemmings that die on that cliff.

I'm going to answer your question, which is it too much to do the wall and the ceiling. I think you can do both because shiplap is just texture. You can dress it up or down and it can be cottage or modern. I think you have to do something with the tray if it doesn't already have a treatment. Another thing to try would be painting inside the tray and installing moulding. I LOVE the pic posted above that says "Atlanta Homes" in the bottom corner. So classic.

There's shiplap that takes on the appearance of a shack and a precise installation that looks sophisticated. You can also stain the boards to take on a different appearance.

I personally wouldn't ship lap a ceiling unless I had the kind of house that really called for it not only in terms of style but also location.

Check out Armstrong ceiling plank for your ceiling. Easy to install. No finishing required.

Shiplap engenders as much of a negative response on Houzz as do shutters or having that 3 inch border on a countertop. If you ask for an opinion, the majority of responses will be NO.
If you like shiplap, all I would suggest is to put it only on a wall, not on a tray ceiling. Both places would be too much.

How could you possibly have too much shiplap?

Do what you love. I saw in the comments some pretty amazing photos showing a whole lot of shiplap that looked a whole lot awesome. If you love it, you should do it. Don't let the opinions of strangers deter you from being happy in life. GO FOR IT!