Most people that want to self host their own email server for personal use (e.g. on a VPS on their own domain) don't have the infrastructure for reverse DNS zon

Most people that want to self host their own email server for personal use (e.g. on a VPS on their own domain) don't have the infrastructure for reverse DNS zones, so I'd argue that DMARC and DKIM are kind of pointless because their email lands in spam anyways once the PTR query on the IP fails to resolve to the same domain because 99% of the time it will be something like ipv4.somehosting-company.com