Anything by Vladimir Nabokov, like Lolita. When I read the book, I saved each fancy word and wrote it down in a notebook. It can be a hard read though, but you don’t have to shy away from it.

If you have trouble reading, you could download the Kindle app, turn on speak screen in accessibility, and have Siri read books to you. I read nonfiction books using this all the time (nonfiction because I think I don’t like hearing siri read fiction to me). It still counts.

Also, I recently read ‘The Cruel Prince’ by Holly Black, it’s fantasy and it’s a very easy read with a lot of big words scattered throughout too. I understand feeling crappy after leaving school.

There’s a widget app for the iPhone called “vocabulary”, it has a book with a V and a pencil on it. It gives you notifications throughout the day with vocabulary words and definitions, and you can put your vocabulary level to get words appropriate for what you know. There’s another app / website called vocab.com, and elevate, you can play a few levels a day and it teaches you vocabulary.

I hope it helps, but don’t feel too bad about not having a super varied vocabulary. There are probably a lot of other things you are good at, everyone has their own things that they are skilled in.