do I NEED to learn fundamentals?

No. You don't even NEED to trade for forex. Nor do you NEED to make money.

But if you want to that's different.

You can learn fundamentals by reading and reading and reading. And about a decade of practice. One way to learn is look up historical market moves and then google for hours to find out what people think caused those moves.

For example: Here's an easy one to start learning with as the research can be done in English:

AUDUSD is down big over 5 years and also down over past year. But it's up over the last month and up this week.

Why?

There are short term fundamentals and long term fundamentals. Long term more reliable. Short term moves more of a coin flip / random walk but short term fundamentals still matter to odds and expected value of trades.

So now spend a few hours and try to figure out what happened to AUDUSD over last few years (long term fundamentals) and what happened over the past few weeks down to day to day basis (short term fundamentals).

Hint: there is no right answer as to why things move. Only more likely reasons why.