I only wear my Apple Watch when I train and I mainly do HIT workouts.
Be aware, Your phone can also contribute steps.
So even though you're only wearing the watch at the gym, your phone has probably been "helping" the rest of the time
go into the health app on the phone and find the steps page
at the bottom of that page, click "show all data", then click a date, it will show you a breakdown of which device contributed the steps
Below that is a data sources and access, it will give you a list of devices, and you can open those and see a total of steps for each day for that device. I seem to have about 20 watch entries, I've only had 4, (series, 0, 3, 3(broke the glass), 5) so not sure if it's every time you do an OS update or how it's broken down, Some entries only have a few days in them.
If you understand XML files, you can export one of those from the health app that will have all your data broken down.
but the file is massive, and you'll need to code your own script to deal with counting the numbers for you.