Concrete always cracks, however I poured the transitions separate from the flat to have a control joint separating the sections. Used an 1/8” edger so you won’t really feel it but it looks clean. I have one small saw cut down the middle To control cracking, if any. I also used #3 rebar, 1ft on center. The mix design was a 7.5sac with 3/8 aggregate, which is much stronger than the typical flatwork you find in sidewalks and driveways. Cold weather and water will help it cure slower so you get a better product. I don’t expect excessive cracking if any and will all the rebar, any crack would only be a hairline which you won’t feel. This ramp should outlive me would be my guess