I had been running mail servers for a few years but didn't bother with my own until about 12 years ago. Back then all I needed was an old box in a cupboard, static IP, mx record and not have an open relay. As you have discovered things have changed a lot.
I have seen some people do cool things with qmail but unless you have a long history with it I think you are better off with postfix. Qmail requires a lot of patches to catch up with the way things are done these days.
It sounds like you have done all the best practice things. A valid PTR record, valid ssl certificate, SPF, DKIM, DMARC. You generally can't host from home anymore because your IP will likely be blacklisted so grab a vps and check your IP is clean. You will want to add ridiculous rate limiting so you don't get sin binned when someone mails to a group. Adding your IP to dnswl probably does not hurt.
Even with you doing everything else right it won't get you instant acceptance somewhere like hotmail. You are going to have to establish a reputation over time with them. Get an email address at all the free services, send emails, make as not spam, check their help websites. View full source of received emails if they let you to see what headers their mail system attached to your messages.
And ofcourse protect your reputation. If you need to send legitimate bulk email use someone like mailchimp and let them deal with any damage.
And this is only the outgoing part. You still have to worry about incoming emails, submission, retrieval, filtering etc.
I do email setups for websites where I need to ensure spam filter free communication with clients and most business mail system I encounter don't seem to bother with half the stuff I do. They will deliver all their emails plain text with no spf or dkim. And they will do brain dead things like having fake blackhole mx records as some sort of homeopathic spam remedy. And they all seem to stay in business so perhaps we just overthink this stuff sometimes.