You can set the minimum extrusion width to a small value (20-25%) for better fill. You could also use classic mode with gap fill. You can use ironing for both to improve the results.
faebudo
Yes, however RFC7208 says not to send NDR when sender authentication fails (=when SPF/DMARC is correctly set up it will fail) So you will get massively less backscatter. There will still be some providers sending NDRs however not the big ones, they will instead inform you via DMARC reporting which is easier to ignore.
Generating non-delivery notifications to forged identities that have
failed the authorization check often constitutes backscatter, i.e.,
nuisance rejection notices that are not actionable. Operators are
strongly advised to avoid such practices
This is great. I already have seen this with some bigger companies that are work from home. Vendors go to their office and use the meeting rooms so they can talk to the employees which work from home.
So now to have IBM as your supplier will cost you more than the competition because you have to provide office space (which you eliminated for your own employees) to them.
I always like it when big companies put stones in their own way with their bad policies.
Use the recommemded parameters: https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-argon2-04#page-11
Also consider WebauthN/Passkeys. They are much less ressource intensive on the server but useless to an attacker when the database is leaked and as such don't rely on slowing down the crypto operations.
Unfortunately many people don't like to think themselves (not that AI would do it).