There was a very light flywheel on my 2016 MX-5 Sport and it took some adjusting to in order to get a smooth 1-2 and 2-3 shift. And....Miatas also had a run of questionable manual trannys anyway in the 2016's and I had mine replaced once under warranty because I just couldn't shift smoothly from 1-2 no matter how hard I tried. Replacing my transmission almost totally solved the issue, but it wasn't the most friendly manual to drive. Certainly not as good as manuals I've experienced in about 4 Accords and Civics I've owned over the years. I just don't think Mazda has mastered manual tranny's, although their cars are superior in almost every other aspect. I've been driving manuals since the mid-seventies, so it wasn't an experience thing with me either. Could it be that 3's have a fairly light flywheel and somewhat the same kinds of issues? I'd take it in and have it looked at. My Mazda 3 GT is auto because I'm getting lazy as I get older, but not because I was avoiding Mazda's manuals. With practice, you can keep the revs up while shifting, but it's not something I had to do with other makes....not sure about your experience. Clearly this is different for you as well, and I suspect you know how to shift properly. It's just different. It certainly was for me.