I got a reply, but it doesnt work for us. Didnt have a chance to try different router though. You can try it if it works for you:
Thank you for contacting Nothing Customer Support.
This correspondence pertains to your inquiry regarding the intermittent Wi-Fi connection of the Nothing Phone (3a).
We extend our sincerest apologies for any inconvenience this matter may have caused. We are committed to assisting you in resolving this issue promptly.
We kindly request that you attempt the troubleshooting steps outlined below to address the issue:
1. Stay close to the router to avoid automatic disconnection due to weak signal.
2. If many devices are connected to the same WiFi network, disconnect them.
3. If you’re using a metal protective case, remove it and try again.
4. Turn the WiFi off and on to check again.
5. Try using another WiFi network. If the issue persists, please contact our Customer Support for further assistance.
Please forget the WiFi connection and reconnect: go to Settings -> Network & internet -> Internet -> Wi-Fi -> Saved networks. Select the Wi-Fi name and choose FORGET. After a bit, reconnect and check if the problem continues.
1. Ensure that you are not too far from the router and avoid obstacles such as walls, as distance and barriers can impact WiFi signal strength.
2. Remove any third-party metallic protective case and check if there is an improvement in the signal.
3. Verify if other phones have the same issue when connected to this router.
4. Try connecting to a different router to see if the problem persists.
Follow the troubleshooting instructions and provide the details of what happened during and after the process.
Looking forward to hearing from you. If you require additional assistance, don’t hesitate to contact us again.