Just to answer the title, the easiest and the “best” way to deploy Meteor in 2020 is on Galaxy. And Atlas for MongoDB. It’s very, very easy in fact, everything just works. Those are production scalable platforms as a service.
Galaxy runs Docker containers and manages them with Kubernetes all on AWS behind the scenes. It configures your SSL cert automagically, you can change the size of container you run on, and change the number of containers manually or by auto-trigger rules you set up. You get access to APM to monitor your app internals for a little extra learning, everyone should at least try Galaxy out for the 1 month for free with all the goodies, so you know what you might be missing without it. It’s a great service, and the Meteor team is working hard & fast to make it even better. @filipenevola has been writing lots of doc updates (check out the Galaxy Docs here)
You can run the tiny cluster long term for as low as $7 a month w/ a yearly payment or just $9 for month to month. That’s 3x lower cost that the recent lowest cost option with Galaxy, so very low cost for such a solid infrastructure.
And Atlas allows you to run a 3 node cluster for free, which works for development and maybe a small internal app user base.
I’ve used both Galaxy & Atlas for years and have never had even 1 issue. On Galaxy I run a Staging app environment, and a Production app environment.
You can shut down your server/environment and then you pay $0 while it is off, turn it back on a week later if you like, and everything is exactly as you left it. So it’s important to realize you only pay while you are actually using the service. That’s exactly how it should be.
Also using Galaxy and paying a tiny amount of $$ for Galaxy is the main revenue source to pay for the Meteor team to keep making Meteor and Galaxy more awesome! So I’m just sharing how much I like the service and why the value seems awesome to me!
You update your app in the cloud with 1 line re-deploys and your users never notice. I think this doesn’t get talked about enough. 
There are other options out there too, but you won’t find a more well updated and maintained service.