2013 mazda 6 gt rough shifting

When I start my car for the first time of the day and drive within the first 1-2 hours, I can feel the car slipping or jerking in and out of gear. It's a fully automatic car with a "manual" mode. I replaced the transmission fluid within the last six months, and I've checked with my own personal code reader, but no error codes are being shown. Does anyone know any reasons why this could be happening AND if possible can be fixed without going to a mechanic.

How many miles?

Was the problem there before you changed the fluid, or did it start after the fluid change?

What transmission fluid did you use when you did the change?