When I first set up Listmonk it was to use with Amazon SES. At the time Amazon would give you free 62,000 emails/mo if you sent them from an EC2 instance. So EC2 was the best server to use. In mid 2023 Amazon ended that, so now you can use whatever server you like, which makes things much easier. It shouldn't be too hard to convert these directions to another server host of your choice.
I used Hetzner with another build, and once my free EC2 year ended the AWS t2.micro cost me $14/mo. Hetzner has better specs and costs me $5/mo, so I added an nginx vhost and moved listmonk to the same server. Here's a $20 credit for Hetzner.
There is also the possibility to use the 1-click installers for their featured hosts: https://listmonk.app/ - listed under "Hosting providers". I'm not familiar with any of them but there are lots of new guides