I completly agree with you. While Hetzner is my actual neighbor as their headquarters is right in the neighboring town, I still use a server at very small scale provider. I have no problem with my email server. I receive some spam here and there, mostly from Russia. But I immediatly block the according IP addresses for some time.
For years I avoided to use any external service to decide whether its Spam or not. But about 2 years ago I started to rely on some of the external Blocklists.
Till today I have no problem sending Email. Even as I don't use DKIM or DMARC.