Components for smartwatch
This is a great idea for a project, but as others have pointed out, you've skipped some crucial steps. Here are the steps I'd follow:

Describe in simple terms what the user will experience, or what problem they can solve, using your invention. (Congrats, you've done this already!)

Create a block diagram of the system. You've done this partially, you know you want a wireless system, with motion sensors and a battery, that can connect to a smartphone, but you're wondering whether to use Bluetooth or WiFi. I'll help you there: use Bluetooth Low Energy (4.x or 5.x) because it takes less power, and you only have room for a tiny battery in a wrist-wearable.

Build a &quot;WORKS LIKE&quot; prototype. This has the desired electrical design, but need not be wearable; in fact, it's usually sprawled out on your workbench. Obtain ready-made PCBs with the components you need (from Adafruit, Sparkfun, SeeedStudio). Hook things up, write the firmware, and try to get it working. You'll end up changing connections, substituting parts, and you'll be glad you didn't rush to build your own PCB.

Build a &quot;LOOKS LIKE&quot; prototype. This has the desired mechanical shape, but may have no electronics at all. This lets you confirm that your design is actually wearable.

Now that you've verified your electrical design and your mechanical concept, you can work on designing your custom PCB, ordering chips instead of ready-made modules, and fitting it all into your case.

If you succeed, and even if you fail, you will have extracted the maximum amount of learning from your project. And that's the point!