I don't completely agree with one of the answers. SAP/ABAP is a field where many clients are searching able people in Germany. There are also several recruitment companies around that specialize on SAP.
But most of them are bigger companies and they are very reluctant to let the people work remotely. That also has to do with the fact, that you will work on systems which are central to their business. Without their SAP systems or when data will got lost, those companies would suffer enormously.
Also, many German companies are very traditional. So they want to have the freelancer in their rooms. Some companies will trust you after a while and you might be allowed to work part-time remote. Very seldom, they will allow for full-remote access after a few months of orientation and trust building.
I explicitly asked an experienced SAP freelancer about the topic because I was thinking about doing some ABAP freelancing myself and he confirmed that is nearly impossible to get a full remote freelancing job in this area in Germany. Also I am looking for job offers and when SAP is involved, the maximum you will normally get are 1-2 days of remote work a week, after they got to know you.
There might be some jobs with 100% remote after on-site training, but they are pretty rare.
One thought about "SAPing" and programming:
Yes, "SAPing" is very often about configuration, because many companies just use the standard system and configure it. But there are also many big corporations that also do programming. The culprit is that those are the biggest SAP users. So those are really big corporations and they do not just hire some freelancer -- but they often have their preferred consulting companies. Those companies of course first use their own programmers and only when those are overworked, they may hire you as sub-contractor. But than again, the big players want you in their own halls. Only with very special knowledge, you might have a chance to get extra treatment.