AWS is very cost efficient for other services (S3,SES,SQS, etc) but virtual machines are not a good deal. You get less RAM & CPU, with the virtualization overhead, and pay a lot more money.
Especially for Postgres if you run some tests with pgbench you can really see the penalty you pay for virtualization.
Maybe the sysadmin skill of being able to build your own infrastructure is becoming a lost art, otherwise I can't explain why people are so in love with paying 5x for less performance.
Hetzner is cheap and reliable in Europe, if you're in North America take a look at OVH. Especially their cost-saving alternative called SoYouStart. You can get 4/8 4.5ghz, 64 RAM and an NVME drive for $65.
(I have no affiliation with OVH, I'm just a customer with almost 100 servers, and it's worked out great for me)