"I'm interest in ArchViz but I heard the market is esepcially underpayed and unstable for that."

From what I hear from the LW groups..

All forms of 3D modelling/visualisation can be badly paid and there is a lot of competition for work. If you can find a niche and good client/employer it can pay well, but mostly not, particularly when you aren't known.

Allied to 3D work are a ton of related disciplines - motion graphics for example , where you can be making advertising and TV graphics, etc.

Really the field is huge, competition is fierce and pay can be poor.

Wonderful as MOI3D is (it is), ask questions in the mainstream modelling visualisation groups, or even just read the posts there - you will come across interesting posts about the industry.

You are likely to be doing very mundane stuff at the start. You are not going to be well paid from the start.

You mention university - ask them about the employment prospects of their graduates and how many are employed in the field one year after graduating.