Germany has lots of energy related challenges but most of those are of a political rather than a technical nature.

Transporting the energy via cables is part of the solution for this and is exactly one of the things where Germany is struggling. A lot of wind capacity is in the north and east; a lot of the demand is further south and west. It's a combination of politics being a problem (this involves lots of federal states and local councils), poor planning, and old energy corporations dragging their heels.

The obvious solutions of putting some cables in place is basically completely blocked on this. Hence you have southern Germany burning expensive coal & gas at the same time the northern part is oversupplying wind power and exporting it to other countries at a discount. E.g. France is importing cheap German power and struggling to export more expensive nuclear power, which is one reason they seem to be shutting down older nuclear plants and gradually shifting to non nuclear renewables. France is of course still a net exporter but nuclear is too expensive for them to export.

The other part of the solution is of course investing in batteries and other forms of energy storage. This evens out peaks in supply and demand much more effectively, cheaper, and faster than any peaker plant can do. Also, vehicle to grid technology could be very interesting mid term as German car manufacturers are about to ramp up EV production to the order of a couple of million cars per year in the next few years. 1 million cars is about 0.5 twh of battery capacity (assuming about 50 kwh per car). A couple of million of EVs plugged into the grid could provide some very serious peak capability (to absorb over supply and provide peak demand). The hardest thing to figure out is proper incentives for this, which is not a technical problem. Long term, there should be zero need to keep legacy gas/coal plants around for this.

Of course, short term cables & batteries are lacking and there is a lot of legacy infrastructure there to be used. This actually keeps the prices higher than they should be. Overall, the picture is improving rapidly. Renewable market share is growing year on year at the cost of basically everything else.

The reason energy prices in Germany remain high is also because it continues to maintain a quite expensive and dirty brown coal infrastructure. The reasons for this situation are also entirely political. Politicians in the areas where this stuff is mined & burned are being pressured to keep that going even though everyone has known for decades that it is a stupendously dirty business that ultimately will have to go. It's been a point of contention between the two governing parties. Basically it's a combination of protecting jobs and big energy companies who are of course shifting investments to renewables but are putting the brakes on to protect their sinking legacy assets.

Basically, there are big German energy companies that are slowly going bankrupt because they are neck deep into stranded assets related to coal that need these high fees just to survive. So, expensive wind plays to their agenda because they get to keep on burning coal for a bit longer.

Yes Germany's early investments in wind were questionable but most of the new capacity is much better and quite competitive in other parts of the world (e.g. the US, the UK, etc.). E.g. Siemens is a big supplier in this space and of course a big German corporation.