OVH and Hetzner are excellent companies. I doubt there would be any problem with them in the future.
People are really quick to forget the fire that destroyed one of their data centers a few years ago and which did not get addressed in any way by OVH for months.
They also learned nothing from it, and are repeating the exact same mistakes.
I stopped hosting even my personal blog on OVH because of how garbage it is.
Now, I have to admit I haven't been a customer of them for 10 years due to exactly this. But yes the fires exposed a lot of the same I left them for.
I left to go to DigitalOcean but it became too expensive and then I found Scaleway which I'm a happy customer of for years now.
E.g. if you're using AWS Cognito then you're not going anywhere.
True, but the AWS pricing doesn't make sense otherwise. If you're not using the managed services, then the value proposition is no longer there. Using those services is what allows you to build massive systems for relatively cheap, with much less staff. We had a project that was to be moved from on-prem to Azure (same deal), it went from thousands of Euros per month to fitting into the a free-tier, but only because we could use managed services. Spinning up the same VMs would cost more than hosting it ourselves.