First I upgraded from 6.6 to 7.0. The ended horribly. Rebuilt with 7.0 and things fell apart again. Most of the custom integration from HACS failed to either load or run correctly. Rebuild again, this time things seemed a little better until I updated to Home Assistant Core version 2021.12.2. It destroyed my configuration and booted into Safe Mode where I am now restoring from a full back up.
So, there is something up with the recent version of HA OS 7.0. I see a lot of posts around this version having issues. Anyone reading this stay clear of HA OS 7.0 until the next release. I lost 72 hours of my life. Your milage may vary.
Running on a Raspberry Pi 4 8Gb, with a 128Gb MicroSD UHS-II, C10, U3, V90, A1. Using the Raspberry Pi power adapter, which is plugged into UPS and I am hard wired over CAT.
My configuration is technically not complex. I have two HACS integrations and four frontends, WebRTC and UniFi Protect, Weather, Slider Button, Digital Clock, and RPI Monitor. I have basic automation to control lights based on time of day, day of week, and home/away. I try to stay away from manually modifying the yaml files. The only one I have is for Spotify.
I started a thread on Github in response to the failed upgrade. Many others started responding to that thread with the same issue. To be fair, I suspect incompatibility (breaking changes) when upgrading and for a fresh install I suspect delays in back-end processes, something that I have noticed with HA OS 7.0. It seems sluggish, especially on reboots and when installing integrations. However, this has not been my experience with past upgrades and/or fresh installs. I feel this build was rushed to meet a year-end stamp just before the holiday.
I have a spare Pi (same as above) that I keep just in case the production one goes south. Iam running HA OS 6.6 for now and will install HA OS 7.0 on my spare to test the waters. I might buy a third Pi as my third spare and run the second one as my QA.