Which practice account should I use as a first time trader?

Hi everyone. I’m wondering where the best place is to open up a practice account as a first time trader?

The most obvious answer is with the broker you intend on trading with when you go live so you can learn their platform, policies, etc.

An alternative consideration in terms of having something you can always go back to and test out new ideas, etc. is a demo that is open-ended with no expiration date. I know Oanda offers those. Not sure which others do.

I have been using thinkorswim for 2 years now. Stocks before and now Forex for the last year and a half.