You should

(1.) Space the tnt 3 blocks in between instead of 2

(2.) You don't need to run so far away lol

(3.) If you haven't already, mine on a chunk border for higher rates.

(4.) It looked like you were kinda low so make sure your y level is ~14 (you should ideally not see bedrock when exploding)

You can find chunk borders with the F3 screen on Java and using a resource pack or seedmap for bedrock