Difficult choice between two dev positions (in the same company)?

Question

Career in IT

Good night everybody. There may be a lot of text, but I will try to describe the situation in as much detail as possible.
At the moment, my project is coming to an end in my department and I was made clear that I would have to go to another department. On the internal exchange, I found 2 more suitable positions for me and accordingly passed interviews for them. (There is already a positive answer to the 1st of them, not yet to the 2nd, but it seems to me that it will be too).
Now more about these positions and the company as a whole.
- The company is quite large with its own data centers, software services for other firms in terms of business for round sums. Positions:
1) Department of Global information services, in general, support for exclusively internal infrastructure, VMware, administration, etc.
They are specifically looking for younger people in terms of software engineering to develop and migrate services to Cloud with Kubernetes, puppet...(). In general automation of VMware processes.
2) The API Management department deals with interfaces between many products. Under the keywords, I would include here specific technology stacks with Java, pluses, as well as distributed systems (rpc, rest, mqtt ...)
In the first department, it seemed to me that they were not quite sure what and how they would implement. They need new people just the same for this purpose. Both I and other employees have little knowledge in this, because there is only 1 engineer on whom all this hangs, and now through training, courses, etc., we will have to do new things together)) In parallel to this, they also hinted that they would not have to don't do administrative tasks if someone in the firm has a problem.
- One of the main factors -> there are younger people. (I'm about to be 30).
In the second department, people are all over 50, or even under 60. A team of purely developers. Many projects, both old (20+ years) and newer ones. The development of something new in the near future, I think, is not foreseen for me (my assumptions). They immediately made it clear that at first I would have to study hundreds of APIs, solve the problems of fat clients, i.e. support "any" of the projects, as well as further improve them, add new functionality, etc.
- Here, from the main criteria, I would emphasize that before that I just worked with many things that they specifically need. Those. if you go from the resume, then according to knowledge, I fit here, if not 100%, but very close. (the only question is the experience and complexity of applications, here they are most likely a cut above what I did before, and the pluses from the university are far from fresh, in general, you will also have to learn a lot, especially because of the volume of finished products)
= > question:I know that there are a lot of experienced people sitting here with a lot of experience in many places. I would like to take a look at your experience. What do you think is the best way to go in such a situation? This choice will be "for a long time", in this company for 4 years and I plan to stay even longer. At interviews, I liked both departments, good people everywhere. But the situation with the 1st department does not scare much because of the lack of vision of specific goals and how everything will develop. In the second one, "interviewers (bosses)", although I also liked it (I didn't see everyone else), but the age difference will still play a role.
What do you think about this situation in general, and what would you do?
ps Employment conditions and salaries will most likely be the same. (firm policy in Europe).

Answer 1

From a career point of view, both options are normal. Therefore, it makes sense to go where they give more money, and if it is the same everywhere, then where the soul lies. You need to understand that this is not a choice for life, but for a very short time. Well, you can always transfer, since personnel are needed everywhere)

Answer 2

In the second section, you will be scoffed at for the way you write.