Ask HN: Popular skills for stable remote work 4h a day?

Can someone advice what skills and exact technologies are the most popular among employers giving part time remote jobs in Europe?

I will be able to work up to 4 hours a day and willing to learn new technologies and skills. I have broad background in IT, basic experience in programming, network and system administration, general computer science knowledge.

I don't want to learn specific language, technology or skills just for one job. I need advice what programming technologies or skills are best for having stable remote job for part time and also possibility to change if needed (for now I will not be able to have full time remote job).

I'm interested in jobs requiring technical skills but also open to more soft skills based types.

Thanks in advance for the answers