Appreciate your input!

Would need more context to be able to give any real advice but on the whole idea here is my 2 cents:

What is needed to store that amount of footage?

Mostly depends the size/quality you're recording but you will need enough to store a month worth of 'any modern camera' footage. (removed the first numbers I suggested, there are too many parameters to be precise. roughly speaking maybe at least 8 to 16To, for 2k and for 4k... roughly because it depends a lot of various parameters like bitrate, codec even what you're recording will have an impact)

And that is without using any backup! What happens to your project if the disk fails, is stolen or whatever, or if the files are corrupted? Will you start from scratch?)

Also, I will need a stand to prop the camera up as I will move it around the apartment

I will be filming myself and my day-to-day life for nearly 24 hours a day and for 30 days.

Imho, if you want non-stop, or close to, you may need more than a single camera/stand: you will Waste a lot of (unrecorded) time by (un)mounting and setting up your camera every time you need to change room or change angle.

You should also consider sound recording, if needed ?

More importantly, you will need proper lighting. No matter the quality of your camera, without proper lighting equipment your image will look like... well, not the best (polite version ;)

Any brands that are reliable and any that I should stay away from?

Why not use an older iPhone? They have real nice integrated camera.

Or much better: a used Lumix GH5 (4k capable): they have an excellent sensor (given enough lighting) and you can pick among many lenses the best one for any situation, they don't risk overheating and you can easily swap SD cards using the two slots (aka auto-backups), plus you can also use them with a third-party AC adapter in place of the battery making it almost perfect for long sessions filming. And they're quite cheap on the used market as most m43 cameras.

Edit: clarifications.