I used to think that but they all have different strength and drawback. It is harder to find exchange with everything on point. Ftx i was just curious to check out but damn except low fees everything about it looks terrible.
Why do you need so many exhcnage accounts or are you just testing what different sites have to offer?
I think most of the main ones (especially for leverage trading) are very similar and it'll be hard to tell the difference between them (especially if you're using something like tradingview or mt4 for analysis/charts).
I just looked overall what different sites had to offer (and how hard they made getting it - like with kyc) to decide which one(s) to use, I'd recommend it rather than registering and kycing with everywhere if you can (there might be good information on search engines too, Youtube was OK for that in the past but then there was a lot of sponsorships).