I can't recall if a Rpi has web Bluetooth.
You might need a ble dongle and the right drivers installing.
You can do it a bunch of ways - since it's Bluetooth LE you can use pretty much any of the ways that you'd connect to a normal Bluetooth LE Espruino device.
There's some code for connecting directly here: https://www.espruino.com/Interfacing#bluetooth-le
You can use Advertising (which is maybe easier for IOS stuff):
or there are loads of tutorials at http://www.espruino.com/Bangle.js2#tutorials
There's also a post on the forum where I showed how to use bthome with Home Assistant on a pi
I have a Raspberry Pi 4 Model B and it works well with Bangle.js 2 and Bangle.js 1 via bluetooth
Yes, the Rpi has built-in bluetooth and everything works out of the box (after installing Raspberry Pi OS)
I want to use this watch to interact with my rasberry pi from the web or in some other way. Is this possible? Or can anyone give me any ideas?