Redundant Git access and repo access can be dealt with by using Artifactory. But then you have to hope Artifactory works. The SaaS offering isn't very stable and self-hosting is a huge pain in the butt.
You could also architect your business not to go down when an upstream vendor goes offline, but maybe I'm crazy.
> You could also architect your business not to go down when an upstream vendor goes offline, but maybe I'm crazy.
This is what I'm wondering the most about honestly. With Azure DevOps we have slots, so if a deployment fails, there is no switch that happens and the current available online version stays online. Something about putting all your eggs in one basket, but if you're going to do it anyway, make sure you handle a pipeline failure cleanly. A failure to build should not take down production, ever.
Used to use Rietveld and now using Gerrit. You have to buy in to that code review methodology and you lose a lot of the other things (issue tracking, CI), but those can be handled elsewhere by better/more-specific tools.
You could also architect your business not to go down when an upstream vendor goes offline, but maybe I'm crazy.