The app Heart Rate On Stream sends your heart rate from your Wear OS watch to your phone and finally to OBS Studio on your pc using the free open-source plugin obs-websocket.
For example you can include your heart rate in your Twitch live stream or simply in video recordings. The app works without an internet connection as the heart rate is transmitted to your PC via your home network.

This app requires:
• OBS Studio version 25.0 or above --> https://obsproject.com
• obs-websocket plugin version 4.8.0 or above (do not use alpha 5.0.0) --> https://github.com/Palakis/obs-websocket/releases

Streamlabs OBS is not supported.

Supported Watches... (last updated 04 January 2022)
Casio: GSW-H1000 | Smart Outdoor Watch WSD-F1 | WSD-F20 | WSD-F21HR | WSD-F30
Fossil: Gen 5 LTE | Gen 5e | Gen 6 | Fossil Q | Sport | Wear | Wear OS by Google
Guess Wear
Huawei: Watch 2
Hublot Big Bang e
LG: Watch Sport | Watch Style | Watch W7
Louis Vuitton Tambour Horizon
Mobvoi TicWatch: C2 | E2/S2 | E3 | S/E | Pro | Pro 3 Cellular/LTE | Pro 3 GPS | Pro 4G | S
Montblanc: SUMMIT | Summit 2+ | Summit Lite
Motorola: Moto 360
Movado: Boss Touch | Connect | Connect 2.0
Nixon The Mission
Oppo: OPPO Watch
Polar: M600
Samsung Galaxy: Watch4 | Watch4 Classic
Suunto: Suunto 7
TAG Heuer Connected: 2020 | Modular 41 | Modular 45

Why not mine?
Your watch does not support real-time measurement or does not run Wear OS.