What is the recommended amount of money you would need to have, before you start to shift away from a robo-advisor to a broker? Any suggestions? And which broker is the best and why?

Hi everyone, I am someone who has saved up for emergency fund, is investing via robo-advisors and is learning how to pick stocks/ETFs.

I have a qn, when I reach a certain amount of money, where should I position my cash in order for it grow?

Example: Emergency funds is placed at Singlife or high saving yield for sure. When my spare cash is at 10k-20k, I will put at robo-advisor. What if my spare cash grows from 30k to 50k or 100k?

Which broker is recommended for low fees & when should I start to move away from robo-advisors?