These sheets were obviously made before Tasha's, before Sidekicks were meant to have 20 levels, I understand it. But right now they're pretty useless at mid-high levels.
The fact that there is not a single fillable sheet it's a problem too, I understand they were meant to be printed and used IRL but right now it's almost impossible to play live and a fillable sheet to keep as a pdf would be extremely useful.
There is no a skill list, which it's essential for sidekicks, especially the Expert.
And last, if you're going to make a product to be used with D&D 5E you should call things as they're called in the game. Ancestry means nothing in D&D 5E, the word you should use is Race. At your table you can use the words you prefer but if you're going to publish something for everyone you should call things with the name used in the game to avoid confusion.
Personally I think the official sheet is more useful than this one for sidekicks.