Picking a broker is not easy, and most retail traders only spend a few minutes picking one, mostly based on glossy advertising or 1000:1 leverage.
Do your due dilligence, this link is a good start:https://www.cftc.gov/sites/default/files/2020-09/01-%20FCM%20Webpage%20Update%20-%20September%202020.pdf
If the broker you are thinking about does not list its capital with the CFTC, would you really want to deposit your funds with them? Check with the local regulator at least for their capital requirement reports.
Next step is to make sure your broker is properly regulated, and I mean with one of the big regulators, not some dodgy one on a Caribbean island somewhere.
The next step is calling that regulator to make sure they have a good record. Check each and every action against them.
The next step is finding out the liquidity providers, do your due dilligence on them, at least call them and check their record with the regulators.
The next step is checking on the corporate side of the business, get a credit report about them from one of the big leading credit agencies.
The next step is calling or visiting them and talk to them.
The next step is opening a small live account and see if your trading style suits their platform/liquidity/spreads etc.
Do your due dilligence or else live with the consequences, just don't come here complaining on these forums about some dodgy broker, if you had gone about your business the right way, you wouldn't be with a dodgy broker in the first place.
Are the big regulated brokers perfect? Of course not, you will have problems with them, at least you have somewhere to go if you can't get it resolved and a broker with a 100 Mn in capital is not going to run of with your 500 bucks.