For a sauna, 80-100C is usually preferrable. 120C is nice in a wood heated sauna, you don't even need to throw water at this point. It's nice & cozy :)

That would be a cold sauna

That is especially true with large organizations where multiple non-technical teams are ordering/configuring products that send email.

Unfortunately it is difficult to solve, unless services stop allowing sending without verifying and forcing proper configuration. That would drive sales to competitors who do not enforce this, though.

SPF/DKIM/DMARC does not prevent sending the spoofed message, though. It is up to the recipient system to filter out the message should the checks fail. Even then, the message often lands into spam instead of being dropped.

They have revealed that already