I will answer to some things

• they’re expensive, but they also outlast most modern laptops. A first gen Sony still fulfills its purpose of reading epubs. So in the end it isn’t as expensive. Secondhand it is also a lot cheaper and again, they don’t age that much
• most readers are waterproof
• e-readers have little storage, but a book is a few MB’s. So even with 16gb, you probably never fill it
• color is fun, but I’d recommend steering away if your end goal is reading books. You need to push the backlight way earlier than on a bw ereader. If you do read comics, it looks like an old newspaper in terms of picture quality. The colors are far from accurate, but you only notice this side by side with the actual comic/phone
• I would steer away from kindles. They’re known to just update and kill your setup. There are plenty of devices in which you can play around without this issue. Kobo and pocketbook are in my opinion the most viable options. Long battery life, supports many formats, supports koreader if you want. Boox is also fun, but due to android the battery life is a lot less. With the boox you’re able to run Android apps though, so you could more easily use it like a notepad with your familiar apps