Just to clarify, when you say one room vs two room, you aren't saying one bedroom vs two bedroom, you are saying a studio/bachelor apartment with a single room for the entire living space vs a one bedroom apartment with living space and a separate bedroom.
A one bedroom apartment with a separate bedroom and living area and a balcony would cost you 21% of your income. So you either live in a relatively expensive area or don't make a ton of money.
Okay, well we can share our personal experiences, but they're highly individual in terms of preferences, so this will really have to come down to your priorities.
As for me, I've lived in A LOT of apartments, and currently DH and I own a one bedroom in a high-rise. For an apartment, it has a large bedroom, an eat-in sized kitchen, and a very large living room, plus an enormous 24 foot balcony.
It would be hard for us to live without all of that, but that's because there are two of us here, and neither of us leave the house for work anymore. It's hard for me to imagine what I would be more willing to give up if I lived alone.
DH uses the balcony more than I do, but that's because I get outside for walks almost every day, plus our complex has a large beautiful garden and lawn that no one uses. Still, it's so nice to just be able to open a door and go outside, even in the winter.
Having the separate rooms is a big deal with two people, but I'm not sure I would care that much if I was alone. DH works from home in the living room now, so my domain during business hours is the bedroom and the kitchen, and I could be quite comfortable with that on my own I think. I've always worked and studied in bed though. When I was studying for my board exams, I don't think I sat in my living room once for several months. I went out on the balcony a lot though at that time because I had no time for walks.
So that's really what it comes down to. If you have to decide between a separate living room and bedroom, or a balcony, the question is: which one is more valuable to your mental health?
Do you have a lifestyle where you get outside a lot like I do? If so, a balcony may be less important. Do you need separate work and sleep areas? If yes, then having those spaces separated by walls may be critical.
Lastly, do you cook?
I do, that's why the big kitchen is a MUST for me. I'm a former chef and quite demanding about my cooking space. One room apartments tend to have miniscule kitchens, so that's a question as well. On top of that, if you cook a lot and don't have a separate bedroom, it's quite difficult to keep your clothes from smelling like food all the time. The one time I lived in a one room apartment, my clothes perpetually smelled like cooked onions and garlic. It was awful, which is why I only did it once. Plus I preferred living with roommates.
Then there's the option of just spending more and having both. This all comes down to how much these factors combined would contribute to your mental health vs the additional cash flow you would have.
That's entirely personal, but also depends on how static your income is. If you expect your income to steadily rise, then that 21% drops over time.
I don't know how rental laws are where you live, but here landlords can only raise rent on existing tenants by a very small amount, but housing costs are rising rapidly, so there's a solid argument to be made for locking in a rate on the kind of place you might want to live for awhile. So consider that kind of thing as well if you think that you will likely end up dissatisfied living without a balcony or separate bedroom and then having to move.
Anyway, that's all I can think of at the moment.
Good luck with your decision, and don't feel pressured to spend as little as possible. Truly decide what's best for *you* and *your* happiness. Not that you should care what we think, but I guarantee that the people here aren't going to judge you for prioritizing renting a decent one bedroom apartment for yourself.
Only you know what's right for you.