Provisioning an EC2 instance or a dedicated server just has the same cost in terms of manhour: running some automation in deployment pipeline, is something that you'll have to setup and maintain.
Be it updating a docker-compose file over ssh with ansible or something else: you have to do it anyway. If you want to cut that cost perhaps try with a starter project from OpenShift or Heroku, but that will also have a bigger cost even than an EC2 instance, and you will still have to take time to ensure your deployment is properly automated, with automated backups as part of the process.
It's always at least two in production if you ever need it to be HA.
Staging just needs n > 1 to test that sharding works at all.
[1] https://forrestbrazeal.com/2019/02/18/cloud-irregular-iam-is...
If it's throwaway then sure, but building your critical infrastructure around a single provider is really bad business hygiene for the sole reason that you can never control for your dependency increasing costs arbitrarily.
Maybe that's fine for most people, people seem to optimise (or value?) developer time over basically anything else so maybe it's something that's already taken into account.
Daily snapshots? For the prices listed you could have an actual hot spare running 24x7 and still save money. This also makes surge-up easier and if you ask nicely a lot of decent dedicated hosting providers will let you shrink without holding you to contract terms.
And even most dedicated servers can optionally come preinstalled with the OS.
$171.83/month of AWS EC2 (+ bw): 8 core CPU 16GB RAM 250 GB SSD https://calculator.s3.amazonaws.com/index.html
24.99€/month of dedicated: 8 core CPU 16GB DDR3 250 GB SSD Basic Unmetered 1 Gbit/sec https://www.online.net/fr/serveurs-dedies/start-2-m-ssd
$809,57/month 20 Core EC2 dedicated instance RAM? Disk? BW? https://aws.amazon.com/fr/ec2/dedicated-hosts/pricing/
234,99€ month dedicated: 2x Intel® Xeon® Silver 4114 20C/40T 128 Go DDR4 ECC 2x 1 To NVMe Premium 1 Gbit/s https://www.online.net/fr/serveurs-dedies/core-5-s
I suppose the rest to 8x is on bandwidth, which is not charged on this kind of servers.