UUID v4 fills almost every bit with random data, except for 6 bits that mark it as version 4. There's no timestamp, MAC address, or other source, just randomness.
That makes it safe to generate anywhere (client, server, edge) without coordination. The chance of two v4 UUIDs colliding is about 1 in 2^122, you'd need to generate billions per second for centuries to even worry.
Downside: v4 IDs don't sort by creation time. If you index by them in a database, inserts scatter across the index. UUID v7 fixes that.