Welcome to the forum.
Budgets are dependent on the individual needs and wants. We have members living on less than $1,000 USD a month. Others much more. $2,000 a month maybe enough for you depending on your activities and location.
When you say “I’m bringing $20,000 USD with me” you don’t actually mean in your pocket I hope. Use an ATM card or other means don’t have a large sum of cash on hand that could get you killed.
Generaly Foreigners may not work in Philippines. There are likely thousands of unemployed skilled Filipino welders looking for work anyway.