> started a new role within a highly dysfunctional organization with no clear responsibility or supervisors
This is an absolutely awesome place to be. You can either get by doing hardly anything or you can do anything you want.
Which are you going to pick?
If you think the organisation is dysfunctional and the job is not what you want to do and offers no growth then you know the answer: time to look for another job.
Layoffs may be coming anyway. At least by looking now you can go in with less pressure.
> no internal SW development made because of de-risking, and everything will be outsourced instead.
Could you argue that your org needs to be automating testing that deliveries meet functional and performance requirements?
1. "OTOH I fear that developing no experience for several years to come is going to leave me stranded"
I believe so too. If you do 4-5 years of "technical writing involving no coding at all nor a particularly deep knowledge of the technology", that's IMO bad if you plan on going back to writing software. You have 5 years experience now, in 5 years it will mean that you haven't coded for half your career. If you want to keep on coding for a while, look for a job now. It doesn't mean it's urgent; you just don't want to stop coding for years.
2. It seems like it's your second company, and the first one was a startup where you burned out. I just want to let you know that not every company is toxic or dysfunctional. There are a ton of stable companies that are interesting and allow you to have a healthy work/life balance. It does exist, don't lose hope and keep looking! It seems like there is no rush, so you are in a good position.
3. "I really like the space sector and would love to stay in it"
My opinion here is that as a software engineer, it's easier to change domain than to compensate for years of non-coding. I.e. I believe it would be better for you to find a nice software engineering position in a different domain for a while and eventually come back to the space sector than to stay in the space sector and stop coding for 5 years. You will learn useful things in another domain, while if you don't code in your domain... you still don't code. Again, not that it is bad to not code, but you seem to be willing to keep coding for a while in your career.
Again my opinion: as software engineers, we will regularly have to choose whether we want to go into less technical roles, typically management. It's always possible to go from more technical to less technical, but once you do, it's very hard to come back. If you want to stay on the technical side, you have to do it now (I mean, in the next year, not in 5).