If you're interested in getting "true" results, perhaps you could do something like this:
name1@website.com
name2@website.com
etc.
In a spreadsheet, you have one column with the number, and another with the company name. You might want to change this up, putting the identifier in different parts of the email address, to avoid similar "canary" signals.
Personally, I use BitWarden to generate usernames for each website, to help keep my fingerprint (somewhat) scrambled. LastPass also has a good username generator. [1] I would just avoid using complete non-sense words, since there might be some amount of human review.