Domain doesn't pick correct database

[killday]

Odoo v.14.0
Ubuntu v.20.04
Postgres
Nginx

Domain added in SaaS/Domains and added to the build.
Configuration:
A record pointing to the server IP
nginx as a proxy for dbfilter
dbfilter = ^%d$

When open domain it goes to: example.com/web/database/selector
At creating the build I gave it a random name. If the build is with the same name as the domain (respectively the database) the domain picks it correctly at open. Is that the correct way of creating build with domain?