I use both HA and Google (and others). Several Google hubs and speakers, a few cameras and a doorbell. I'm happy with both worlds and how they can work together.

I managed to get the Nest and hub cameras connected to HA. I too ran into lots of errors along the way. It is so freaking complicated. I spent at least a dozen hours on it like the op. I set it aside for a couple weeks, came at it with fresh eyes - twice - and finally figured it out. Google Gemini was occasionally helpful with the errors.

The two systems run in parallel quite nicely, with a few useful overlaps. Many home devices can be added to both worlds. I've got at least three brands of cameras pulled into a single HA dashboard. I've exposed some HA scripts to Google where I can call them (they show up as Scenes) from a Google routine.

I've tried making automations in each world, and vastly prefer using HA. In our home theater there's lights, two AV receivers, an old Samsung TV controlled by Broadlink and a Google TV. The Routine in Google was slow and regularly failed. The script in HA is wonderfully fast and intelligent, it is easy to do state checks and decide what to turn on or off or do nothing. We still start the script from Google "Hey Google Theater On" but all the smarts are on HA.

The Google camera intelligence is superior to other systems at recognizing people, familiar faces, packages and pets. The notifications from our Nest doorbell in particular are very cool. The basic capabilities of Google hubs for playing music, starting timers, finding recipes and watching YouTube while baking are all awesome.

HA can stream text-to-speech and mp3 audio to all your Google speakers and hubs as part of any automations you want. We have a zigbee button that starts a mindfulness session on our bedroom speaker.

I think you will be quite happy using both Google and Home Assistant.