That does not exist and everyone is free to create.
That sounds like a very very special case. All my contacts are easily and automatically backed-up using Davx5 with my posteo account.
Just do some search and reading here in the forum thats discussed in tons of threads. There are more or less convient options. When you dont use google backup or are rootet, you need a bit more manual tools. So if you really have no backups, do this irrespective of updating the phone or not.
What I do: my pictures are uploaded automatically in my Hidrive.
Whatsapp, Signal and 1-2 other apps back-ups are copied to my PC from time to time, might be possible to do this through Hidrive as well never tested it.
Other important documents I upload to my Hidrive
So I dont always have a very up to date backup of whatsapp e.g. however I’m aware and would survive this loss.