Pre or post Brexit ?
Post Brexit, and depending on what arrangement the UK comes to with the EU it could be like trying to get a job in the United States. You could enter the country on a tourist visa (or tourist visa waiver) but if you wanted to work legally then you'd have to go through the hoops of getting an appropriate work visa. In Germany, as a non-EU worker, this is difficult and complicated. You and/or your employer have to demonstrate that the role you want to fill couldn't be performed by an EU citizen. This process is time consuming and while it may be worthwhile if you're recruiting someone with very specialist skills that are in short supply (for example scoring goals in the Bundesliega), for more run of the mill posts it may not be worth your prospective employer's time and effort to do it.
Pre Brexit you would have the same rights as you currently have AFAIK BUT unless agreement is reached between the EU and UK you may not have those rights post-Brexit. I don't think anyone wants to see hundreds or thousands of deportations but you may lose your right to reside or there could be some kind of fudge that you have the right to work and reside but it's tied to your current job.
The trouble is that until the negotiations are complete, no-one knows.
All of the above is merely IMO