I’d have to agree that starting to learn all about FX while you are not fully proficient at actual mixing/transitioning is starting at the wrong end of the scale.
FX should, imho, be used sparingly anyway. The lure of having many an effect at your disposable makes it very simple to over-do things in that respect. I can go gigs without ever touching the FX (bar filters), it’s that (non)important to me.
For some it’s more important and in that case you really have to learn your FX well. But you can only do that when you understand the basic mechanics of mixing.
My suggestion would be to take a look at the How To Digigal DJ Fast course. It comes with a full, no questions asked, money-back guarantee, so there is no real risk of it not bringing you what you’d want/expect.
The course can help you get where you want to be in a couple of weeks, provided you do the (home)work, i.e. practice.