Apple Watch step counter

I recently was gifted a used series 5 Apple Watch and I have observed in the few days I’ve been wearing it that it counts WAY more activity in the fitness app than just my iPhone did. I work from home and don’t take a lot of steps throughout the day, so it always required effort to close that ring of just 120 calories. Now that I have my Apple Watch, that ring closes by noon and I’ve done the same amount of movement as I did before. Which read is more accurate? I’ve seen lots of posts of people thinking the Apple Watch & iPhone double count steps when they don’t, so I imagine other people are seeing this issue. I obviously move my arm more than I take steps, so is it counting all my arm movements as steps? That doesn’t seem very accurate. Any info would be greatly appreciated!