Hello Michal. Are you using Windows 10 or 11? There might be an incompatibility issue. And since you have checked almost everything by updating and reinstalling the drivers and also Windows troubleshooting, the best course of action would be taking a look into this article from official ASUS website - [Motherboard] How to solve the Bluetooth problem of the motherboard? and if the provided solutions still won't work, you may try to Contact Support from them.
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Best regards,