I've been an open source developer for a long time now and enabled gh Sponsors around end of 2021. My most popular projects have around 1.3k and 450 stars. I claimed to donate all sponsored money to charity and in 2022/2023 when I was actively developing I earned around €260 in total and donated the full amount.
After my second child was born I did not have any time for developing any software. There were still some sponsors, but most of them canceled their sponsorships pretty quick (which was totally OK).
So I would say it depends on your projects, your luck and your consolistency how much you can earn, but i'm pretty sure your earnings will be nowhere near what you could earn by having a job or being a freelancer.
So if money is your primary motivation, I would pick freelancing/working for a company...
The amount of money you will get via donations will be either zero, or a rounding error from zero.
Donations is not a business model.
As you are a student, you may gain other benefits though. All programmers go through 3 stages;
1) you program to prove to yourself that you can. 2) you program to prove yo others that you can 3) you program because your output has value. (Ie you program for money.)
Indicentally there are lots of employed programmers who get stuck at level 2. They're forever doing work that adds no value, simply because they want to prove they can.
99% of Open Source has no value, but can be a valuable way to demonstrate your ability.