I have attached a pic to better illustrate my point. You can see the shade next to the rock and on the edge where the substrate ends next to it I could actually keep a medium to high light plant. This is a high tek setup.
Anubia is the most shade tolerant plants and I have some thrive under permanent shade from taller plants. Like yours, mine is not dark shade but bright shade due to reflection from the white substrate and glass walls. Another good shade tolerant plant I have is Trident Java fern which also do well under canopy. Crypt, Bolbitis and Buce are low light but not shade tolerant IME and won’t make it under shade.
Light and dark, shade or light are all relative terms and we can see how it effects plants when we look outside. Some plants do well, some don't in any situation.
I find there are always going to be changes going on in fast growing plants like our tanks often use, so I have a choice to redo the plants I use, redo the lights or adapt in other ways. One way is to use low light plants in that spot but if you don't find any you favor for that, you can also alter the site without going to the trouble of rebuilding the whole tank. Adding and extra light on your tank would not be what worked for me, so I might look at a rock on the side of this one and then plant on the top of that rock where it is now lighted!
Abit more complex for shopping but a rock with a hole in the top would give a broader range of plants to shop for the location as many of our tank plants need very little soil to grow. I love wood and find it easy to work, so my choice would be wood with a hollowed out spot at the top as that often happens in nature.
Lots of personal choice and YOU are the master of that world!