There are two ways to generate a World.
I've used both in the first two releases so far and it does stall for awhile in the 8x% area (road smoothing), but does finishing after a little bit.
I have a fairly new machine (i7 13700k, 32 GB, 4070Ti) and it takes me about 5 - 10 minutes to do a 10k Map.
I've seen a few people doing 15k Maps, but not sure how long that took or what their hardware was like.
So anyway, depending on what you have, it may take longer.
Yea, A20 took quite some time to generate a 10k Map.
Different hardware, but it took a really long time.