@olessko I found myself in the same boat a little more than a year ago, but I live in the south of Germany and for a German MNC Giant. I essentially slowly offloaded all my responsibilities off to my colleagues, and focused on specific skills I wanted to develop and practice. And, that left me with a lot of free time time at work, which I then used for checking out some alternate domains and emerging tech, as well trying out some new roles, and communication styles. I also got a lot of time to read more, plan things outside work, thereby meeting more people, traveled a lot more, spend more time with my family around the world combining it with remote work.
Maybe there are some improvements(communication,management-style...) that you wanna try out without getting worried about pissing people off or risking your career in the company. Another option is to, get certified in something new, a Scrum Master or so would almost definitely not give you a pay-raise, but might open up some new doors to transition in to something else, or round your profile up. I did consider getting a master specialization on the side, but the compatibility with the German system made it kinda difficult for me.
If you extend your search to the south, especially in the IT divisions of the Automotive Companies, they would have some jobs in whatever niche experience you bring to. Depending on how you fit in to their Vision/Org-setup you would be able to keep your current salary. Chances are, unless you are in to Big-Data/AI/Machine-Vision(or any of the Innovative areas), you wouldn't be able to higher offer, and you might lose some flexibility. But, on the plus side, the are more chances to develop your career further ahead, or take up well defined roles in a structured organization. These may or may not be what you might be excited about now, it is still worth its value in the German career market, especially in these big companies with all their processes and internal politics.
There are also Inno-tech firms that let you work remotely, and match your current pay grade with a different workstyle and organizational structure, that you might be interested in.
Finally relax a bit, use the time to figure out what you want, and sometimes going "up" would require stepping down(could be salary, perks,Job-title,other expectations..) a bit so that newer ways of going up opens up. I remember telling myself, that once the boredom, monotony and bad feeling get too difficult for me to bear with, I would find some internal motivation to get myself out of the "cage".
PS: In my case, i looked around inside the larger Organization(read Central), attended a few interviews, and one of them lead me to a yet-to-be-open position, where will I take up more responsibility, have higher visibility and report higher-up than now, albeit without a pay raise. I am starting next month, but am looking forward to this change, and a fresh start