Mac mini M1 wifi connect issues (possible device interference issues)

Thank you for your fast response. I would try to run the wireless diagnostics with two different HDMI setup tonight to see if I can have two different result, then I can make sure is the HDMI cable. And I think I may check the wifi connection in recovery mode to make sure that it is not a hardware issues.

Thanks again.

Thank you so much for your help and advice. I switched my HDMI cable from Belkin to BestBuy Insignia, and so far so good, ZERO down time so far since last night. And I move the mini to another location on table far away from other devices, ups and cables. Only cables connected to mini will be binding together using cable tie instead of binding all together with other tables like before.

And I brought a mini stand from Amazon so I can put the mini vertically as your mentioned to increase its wifi performance. I'm so glad its not a hardware issues.

For anyone else who has similar issues, followed den.thed and hcsitas advices, make sure it's not a hardware issue and the router has been properly setup.

Because how mini been designed, wifi and bluetooth are really closed to HDMI and USB3.0 ports as den.thed mentioned, cable switch only work if there is no hardware issues. If your mini CAN connect and stay connect to 5GHZ network, but no internet or cannot send or receive data (webpage loading stuck or took forever, video streaming keep reloading or stuck), or suddenly disconnect from network but still connect to the wifi and other devices connected to the same network is working fine, and switch to 2.4GHZ works fine or switch to 2.4GHZ and switch back to 5GHZ will keep your network connect for a moment, then probably there is something interfere with mini wifi performance. Please disconnect everything from mini except power cord and HDMI, and if problem persists, switch to different HDMI cable to see if wifi is working normally.

Like hcsitas mentioned, sometime, old routers will have poor performance especially those are already end-of-life. Networking and Wifi technology will keeping updating constantly. And for most of time, new standard like 802.11 n, ac or ax will have downward compatibility so if your old device only support up to n, then it can still using router that comes with ax, however, if you have newer device that support ac or even ax, but the router only support n or b, the performance will be impact and sometime will causing unexpected behaviour like mine did.

Thank you so much for your help and advice. Yes, I agree with you, my router EA9300 do have issues with its Wifi performance, and that is the reason why it has been reset two days ago, my desktop keep having issues with 5ghz network. You know its wired, I have another router as my main router that has been using for almost 7 years, Asus RT66U, still working like a charm, never have issues like Linksys EA9300 did to me. I already order a new one last night from BestBuy, it's time for me to say goodbye as I can't even find the its product page on Linksys website.

Placing Mac mini or any device connect to 5GHZ just like buying a house, it's all about location, location, location. Hope I can still keep that ratio after new router is here ;)

Looks normal to me at this point, while Mac mini still having issues. Router (Linksys EA9300) has been reset two days ago.

I will, thanks again and all the best to you too.