Hi PatrikDósa,
Welcome to post in Microsoft Community.
I'm Mosken, I do apologize for the inconvenience that you're experiencing right now, let me help you figure it out.
According to your description, I knew that you have 3 bluetooth devices connected simultaneously on one Windows 10 device, but the mouse is often not recognized and you want to change the priority of these devices. If my understanding is wrong, please correct me in the reply.
Sorry, the Windows system itself does not provide such a setting. Moreover, the overly complex electromagnetic environment will affect the Bluetooth device, resulting in abnormal connection.
Try troubleshooting the Bluetooth functionality first. Win + Q to open the search box, enter "troubleshoot Bluetooth", then select "Found and fix problem with Bluetooth devices" in the search results, and follow the prompts.
Then you suggest that you try to remove all bluetooth devices, clean up related drivers, restart, and add devices again. This may repair potentially corrupt, conflicting driver files.
Then it is recommended that you try to update the drivers of these bluetooth devices. You can go to the official website of your device manufacturer to download the corresponding model driver, and then install it manually. After the driver installation is complete, it is recommended that you check if the device works properly, and then restart to check again.
In addition, you can try to create a new test account, because this cannot be ruled out because the account configuration is wrong. You can visit **** Create a local user or administrator account in Windows (microsoft.com) **** for more details.
Then you can visit Fix Bluetooth problems in Windows(microsoft.com) for more troubleshooting on bluetooth connection, hope it will help you.
The above steps are provided based on the information I have learned so far, I wish that will be helpful to you. If your problem still cannot be solved by these steps, you could tell me the specific situation in the next reply. I will continue to assist you in solving the problem.
Best Regards,
Mosken- MSFT | Microsoft Community Support Specialist