I find that the keyboards of today give you all you need to do a great job; no mixer needed. Rooms are different and that’s why we are given master EQ’s and master reverb controls.

You set up your set up in the largest room you have, and then use the options to adjust to what you want. A mixer gives you work and problems that are difficult to adjust on the job. Not needed.
OMHO, John C.

PS, One stand, one Keyboard, one Speaker, one Mic, and one wire from keyboard to the powered speaker --- and one wire for the mic. Oh, and yes the music.

But since us humans are not all wired the same way – whatever makes you happy rules!