What is the max number of contacts that NextCloud can successfully work with?
I would say it depends on the server
What do you mean exactly?
The theoretically size is the first reached limit below:
- the maximum ram, that can php&co. assign with the architecture of available processors
- maximum table-size of mysql database
- maximum filesize limited by the filesystem (NTFS 18,0EB; FAT32 ~4GiB; ext4 1EiB)
some of these limits for the client too
Practically: it depends on the Server.