No response to after PhD interview, Germany
I was a candidate in an application process at a university in Bavaria a few years ago. After the interview, more than a year went by without me hearing anything from them. I wrote them a letter formally withdrawing my candidacy, since in this time I had already found a good job elsewhere.

I later learned through the grapevine that someone else was ranked first in the process, but negotiations between them and the university took forever. Once negotiations were finished, the official job offer still had to wait until the faculty council approved the offer, and this council met only every second month. Thereafter, the offer had to be sent out, and the offer had to be accepted. All this bureaucracy made things take forever.

"Thanks for your patience" tells me that you are still on the reserve list as a suitable candidate; you're not (yet) rejected. However, it's quite likely that someone else is the preferred candidate. Negotiations with this candidate are ongoing, and unless they don't manage to work it out, the job will not be yours. I would start looking elsewhere.