How should I properly prepare for the cat that I am planning to adopt?

For context, I have had cats before when I was younger but they did not have the best life (or at least to my standards) that I could have given them (I was a child and the only litter sand I can provide was actual sand and their food consists of what I eat (lest the occasional cat food when I have extra lunch money from school)).

Most of the cats I got were also from the streets and so they have the usual training from the mama cats and don't really need any more attention except for giving them food, cleaning their litter, and the daily pets. I live very far from my hometown and the cats have weirdly ran away from our house after I graduated. Since then I've been thinking of getting a new cat but I want to do it right (also since there are more restrictions in my new living space), I want to know the following:

1. What unexpected thing/material do I need to prepare for the cat (which isn't the usual cat litter, bed, toys, etc)?
2. Which routines should I build especially if ever I'm getting a kitten? I want them to be well adjusted to people since I live in a shared space, the only real privacy is my bedspace.
3. Should I even get them at all? Or should I wait a few more years (like 5 years) to have my own space to do all of the things correctly. I wouldn't want my cat to live in a bad or not ideal environment just because I want a cat.
4. Should I adopt or shop? I know the answer should be adopt but my building requires strict documentation for a tenant to actually allow a pet inside. Adopting is cheaper but it does not guarantee that I will have all the documents that I need which would require me to process the papers myself and by then, where does my cat stay? If I shop then the documents are guaranteed but its much more expensive.

Am I overthinking this? Should I just get a cat? Should I wait for my own place which could take ages? I've never had to document my cats before so this is new to me somehow 🥲. Advices are greatly appreciated.

me rn