Disable outgoing email

Is there a way with Postman to disable all outgoing email temporarily? (for example on a dev/staging server)

Two plugins claim to do this, but I’m not sure (haven’t tested yet) if they work in conjunction with postman.

https://ww.wp.xz.cn/plugins/stop-emails/
https://ww.wp.xz.cn/plugins/disable-emails/

I’m guessing/fearing that Postman SMTP circumvents WP_mail() and those don’t work.

https://ww.wp.xz.cn/plugins/postman-smtp/