Things you should never do: use integers as ID's. This is literally a solved problem, and the solution is UUIDs, which were invented for exactly this job.
ULID. 128bit, human "readable", sorted (like int!), nearly impossible to guess/collide and has timestamp embedded. I love this format.
Here’s a link to a description of ULID, for those like me who had never heard of it: https://github.com/ulid/spec