I would suggest having the first 2 interviews at places that are lower on your rank list to get the jitters out of the way.
It will help you see the Qs they ask, maybe polish up your responses, find gaps in your application that you will be asked to explains etc.
The middle chunk should be your top X schools which will allow you to still be fresh enough on the interview trail that you aren’t burnt out (or is it all on Zoom now?)
Then if time (and $) allows, can have your last 2-3 be “reach” schools, so if something unexpected comes up, $ runs low, preceptor doesn’t give time off etc, you aren’t losing a spot at a place you could have easily matched.
Agree with not using any services.
Is there any one on the faculty that you can approach, preferably someone on your school’s admit committee?