Thank you @jshaffstall
I was returning the iterator this entire time and the performance was bad.
Looking through the forum, I found a topic where returning dictionaries was suggested. But it hasnt improved anything.
Below is a new clone with your suggested change. Is the performance acceptable for a small table with 500 rows? Will it be better if I were to retrieve only a few columns?
https://anvil.works/build#clone:PL4RM3BSN5W4UFXR=RL3QTSDME2LFYARX5TQFSB57