The real reason fillers appear
Fillers usually appear when your mouth moves faster than your next thought. The answer is not panic or shame. The answer is to practise a short pause until silence feels normal.
A better replacement
Replace uh and um with a closed-mouth pause. Replace like with for example when you are giving proof. Replace basically with in simple terms only when it makes the sentence clearer.
The drill
Record a one-minute answer, count your fillers, read the transcript, then retry the same topic. Most speakers improve faster when they repeat the same idea instead of jumping to a new prompt.