Any solution to Google and WiFi being unable to connect? Speed limit indicator stick at 20 mph. Overall acting glitchy. Issues started 15 months after taking new ownership. I have tried the re set suggested by GMC bit that didn’t solve issue. Dealership wants me to leave for several days to run diagnostics. Any DIY tools to troubleshoot? Thanks in advance.

If I had to guess, the infotainment stack is going bad or possibly the antenna(*) have issues.

I would get it to the dealer for this and get them to fix it before the warranty runs out, especially the speed limit indicator.

You could try stuff, waste a bunch of time, then take it to them too late.

If they can't fix it, at least you have it documented that you took it to them. This can help later.