Don't use the SDK Manager - unless you have a very specific need, or are specifically directed to (by a B4A tutorial, example, forum trusted user)
If you are expert enough to have one of those needs, you will know how and When the SDK manager needs to be used.
Best delete your 'Android' Folder completely and re-create it following Step 2 here:
https://www.b4x.com/b4a.html
The "Command Line Tools" and "Required Resources" downloads constitute the whole standard Android Environment required by B4A.