Reddit mentions of MoKo Holder Case Fit Apple Pencil/Apple Pencil 2, PU Leather Case for Samsung Stylus Pen Surface Pen, Fit iPad 10.2 2019/iPad Air (3rd Gen) 10.5"/iPad Pro 11 2020/iPad Pro 12.9 2020 Pencil - Black

I have not found any cases that are slim and yet not compromise safety.

At the moment I use a UAG metropolis case for my iPad 2018 (https://www.amazon.com/dp/B06XYRHP7C/) and a cheap case for my iPad 2017 (https://www.amazon.com/dp/B079MB43RM/).

The cheap case is temporary because I'm currently living in another country for university, and I left my other UAG metropolis at home. When I get home during the summer or next year, I'll be replacing it with a new UAG case.

The cheaper case feels very flimsy to me that I'm not very confident that I want to bring my iPad 2017 outside. I can't imagine how people actually use Smart Covers and nothing else. But that's just my preference.

My UAG case has been time tested though, I fell twice on the pavement (yes, I read when walking to my exam hall, fell when I did not see the large dip on the pavement) and both times, my iPad came off pristine and unscratched, while both my knees were totally scraped. So I know for sure that my iPad is pretty safe inside the case.

The trade off - it's pretty heavy. I calculated that if I carry iPad 2018 + Logitech K380 + UAG case, it'll work out close to about 1.1 to 1.2kg, which is almost as heavy as my MacBook Air 2010.

Also one thing that bothers me with the cheap case is that it only covers 3 sides of the iPad: top, right and bottom sides. When you close the lid, the left side is covered of course, but when you open the lid and fold it, the left side is exposed. So if you read on the bed or you use it on the table, some dirt and crumbs can stick to the exposed side (I buy the case for protection and to keep my iPad clean and pristine, but it's useless if one side gets dirty).

I only found out about this after I bought it. I did not scrutinize the product pictures on amazon. Next time make sure to check all the sides on the Amazon product pictures. I only discovered recently that if I had paid more attention to all the product pictures, I would not have bought the cheaper case because of the exposed side when you folded it.

UAG Metropolis covers all sides of the iPad (with both folded and unfolded cover), so when you read on the bed or when you put your iPad on the crummy table in McDonalds with the cover folded, you know your iPad will stay clean.

The bad thing about UAG Metropolis - the iPad 2018 case does not come with a pencil holder, so if your kid is the kind of person who always loses stuff, you might be better off getting a Fintie case. I have not found a good case for iPad 2018 which can replace my UAG and comes with a Pencil Holder. I did not get a Fintie case because I wanted to get a silicone tip cover for my Pencil and Fintie case Pencil Holder would not fit that.

I have a separate Pencil case for my Apple Pencil (https://www.amazon.com/dp/B06XQXM89Z/). Since I'm in school I also use it to carry a real pen or two (for exams), my Lightning USB cable and a microfiber cloth in there.

I also bought this (https://www.amazon.com/dp/B06XJDNQ2L/). I replaced my Apple Pencil Lightning Cap with this one, and I use the silicone tip to protect my Apple Pencil tip, because I've heard that if you drop it on the tip, it's a goner. It also helps the Pencil not to roll over the table.

See my other post here about using the same silicone tip to dampen the sound of the Apple Pencil against the iPad surface, so your kid can use it to study in the library

https://www.reddit.com/r/ipad/comments/8ilhvl/ipad_2018_screen_with_pencil/dytgmda/?st=jh2rge9i&sh=8195346a

I used to be like that too, I'm on my fifth pen now. I ended up buying a case for all my surface accessories and pens. I've formed a habit of placing it in the case and checking the case before I leave anywhere I do work. I also put a tile locator in it incase I lose the case. It seems to help so far.
Something like this is what I got:

https://www.amazon.com/MoKo-Leather-Samsung-Surface-Generation/dp/B06XQXM89Z/ref=mp_s_a_1_4?keywords=surface+pen+case+holder&qid=1570129772&s=gateway&sprefix=Surface+pen+case&sr=8-4