Sending 1M+ emails a month...Help

So I've spent the last few days having people throw monikers like SMTP, DKIM, and SPF at me and Im overwhelmed at this point. Ive talked to SendGrid, Ive looked into Sendy and SES. Ive researched leasing a seasoned email server, and I still don't know what the best option for me is. Warming IPs is a separate issue so I want to start with just getting my feet on the right path.

Any advice is greatly appreciated. If you can give me a hand on building this, even better.

Trust me sending 1M+ Emails is easy. Having the right configuration and set up is tough. You know what's tougher having the emails to inbox and conceptualizing a strategy that makes things work in tandem. Setting up and Maintenance constitute to be major tasks and monitoring content and list to maintain the server hygiene is extremely crucial.
Happy to help if you are still looking.
Cheers!