Capacity, Performance, Backup & Bubble Platform References

I am very concerned about future performance if I develop an app using the Bubble platform.

Can you point me to references that are using Bubble to the max – presumably the Production Plan with 10 server units & capable of adding 30 units – for 40 units total? Companies & contact info?

By the way, what exactly is a Server Unit? What is the best performance with the number of records? What is the cost of extra Server Units.

Also, I am particularly concerned with storage – the number of gigabytes used.

And, how is backup achieved? Frequency? Offsite? To a second country or Europe? Ability to 100% recover? Cost to backup? Cost to 100% recover?