I had similar thoughts, but how does one use an RDBMS without making use of FKs? Do they put all in one huuuge table, that has all the columns and is super sparse? Or some other fever dream of bad design?
As long as you don't give a shit about data integrity, you don't need foreign keys.
You can have a field with some value that just happens to match the id in a different table. That something could be a foreign key or just a number.