(based) on Is based optional?

Hi

Could someone please help me correct these sentences with "based on"?

1)

In an ad :

Looking for a assistant for different projects around the city.

Paid job based on/according to the number of hours and location. (How would you say this?)

2)

People judge me (based) on/by my profile picture.

Don't judge someone on/by a picture.

3)

Is based on what you would use? Is based optional?

The voting at the Eurovision isn’t based on talent. It’s more political.

Judges are going to vote (based) on 3 criteria.

How would you say this? Is based optional?

We judge an attacker by/(based) on the number of goals they score.

4)

I read this sentence online. Is it correct to say “voting based on geopolitics”? or “according to” or would you phrase differently?

I would expect bloc voting (based) on geopolitics to be even more prevalent in Asia, if anything.

Thank you