You can fill data table from CSV JSON or from google docs (well something from google online tools).
You can also make editor tool widget to create players in easier way.
Also blueprint pic is too low res for me to read tiny and pixelated text, so no help with that.
However this may help with data tables:
this is about unreal and CSV importing to data tables:
Unreal docs about JSON plugin:
Personally i wrote tiny json code in c++ (basically exposing json function to blueprints and declaring structs there in C++). This solves loading data, but it needs some asset manager tweaking so json file gets packaged.
Ps.
Consider using data assets for players, then fill teams with info from Data Asset. This way you can have single Data Asset per player, and data table that holds just players ids, rest would be loaded from players data asset.
This “WTF is” guy made excellent tutorials about data assets and data assets created in blueprints (which can contain some blueprint code)