Spousal visa student at a foreign university

Hello
Firstly, apologies for the title as it may not tell the whole story but the character limit prevented a more detailed explanation.

I am German national (male, 23yo) currently finishing my final year at a regular Swiss University. This final year I can complete almost entirely remotely. Last year I did an exchange semester in Japan and met my current Japanese girlfriend (25yo) while she was finishing her degree at my exchange University. Since April she has started working at a well-known Japanese company.

We are closing in on the one year mark and have lived together for a total of 6 months (first on my student visa, then I applied for the change of status to temporary visitor once my program finished). We are attempting to have me stay another year in Japan. We have drawn a plan of the future together (including her moving to Europe with me once I finish my studies and find a job) and have considered marrying soon.

Since most of the posts I've found on this forum regarding spousal visa questions and concerns like having no income and being unemployed are usually related to non-students this brings me to my main question.
Has anyone heard of a scenario like this: Technically a student at a foreign University, with no employment or income trying to apply for a spousal visa

A second question arises regarding the proof of income and tax returns of my girlfriend, since she hasn't worked at her company for more than a year yet and thus has no yearly tax returns. In this case, her parents will have to act as her guarantor?

I am aware that this forum does not represent the decisions of the immigration officers, but I am simply inquiring whether or not a scenario like this seems similar to any of the forum users here.

I also understand that some people might bring up concerns regarding the speed of us wanting to marry and our rather young age. I appreciate the concern, yet both of our parents married early and fast and live happy lives to this day.

I apologize in advance for any misunderstandings or uncertainties in my questions and appreciate any answers or advice.

scenario like this: Technically a student at a foreign University, with no employment or income trying to apply for a spousal visa
yes, many have done it.

In this case, her parents will have to act as her guarantor?
yes, that is normally the case. Your gf/future wife can also submit supporting document as well as proof or employment/income.

As long as you have all the documentation ready/ genuine marriage, it is all up to immigration bureau to accept/process your application, BUT problem will be whether immigration will allow change of status(inside Japan) or ask you to go the 'standard' COE-visa route(you have to leave Japan) is up to immigration perusal.

So first get married, which it itself require/cause of documentation headache.

Good luck

the important things are :
1. the marriage is proved legally in Japan and preferably also in your country.
2. you (you and your spouse) will have enough income to live in Japan. (income matter)

1. it is easy, if the marriage is genuine.
2. primarily, immigration asks your spouse (a Japanese) income. immigration accepts the official documents. but, she has nothing.
in that case, she may provide the private documents (i.e. her company's documents ).
在職証明書 and monthly 給与明細, from her company.
secondary, you can add your (a foreigner's) income. in this case, it is not applicable. you have no income.
thirdly, you can add her parent's (Japanese) income. the documents must be the ones which are issued by the officials. also, her parents can (should) write some 理由書 which shows that her parents celebrate the marriage and they promise that they support you financially.

I presume that she graduate the graduate school (master program) of well-known university and get a job in well-known company as a new employee. if so, immigration trust the company's documents. ( I think her working condition is un-limit until her retirement. her salary will increase every year. )
additionally, when her parents write a letter which celebrates the marriage, it supports the marriage's genuineness.
in general, the parents of well-known university students are richer than those of other non-well known university students. and actually they were rich enough to support her financially until her graduated-school graduation. (it is common in Japan.)

when my expectations are all fit to your case, immigration will grant the spouse application surely.

P.S. in this case,
she is a guarantor about your personality and her parents are guarantors in financial matter. you write her name as a guarantor and add supplementally her parents names (one of high income person is fine.)