Is there a site where I can simply upload and run the server?

How about Google Cloud Platform (GCP)?

There's a year's experience (just give me $300 credit) and even after the experience, you can use a low-end server for free with US Revision. :D

The downside is that there is no server in Korea.

https://cloud.google.com/compute/pricing

AWS is good, too. You can only experience it for a year here. You can open a server in Korea, too.

You have to be careful when you use AWS, because we have decided on a service that you can use for free, not a way to give credit, so if you pass this, you'll be charged right away.

https://aws.amazon.com/ko/ec2/

Naver has a similar service. The advantage is that one Korean server is free. I don't think I have a year's experience.

(Additional: I see it now!) I don't know if it evaporates after a year, but it says it gives 300,000 won credit. It also says that you can use the free server for only one year.)

https://www.ncloud.com/charge/price/ko

Personally, I'm using GCP right now. I put a lot of images on the Japanese server and run a small web server, and it costs 6,000 won per month.

For your information, AWS has Korean manual and GCP has Korean management console. NAVER is all Korean.

I've never used Naver Cloud, so it's kind of hard to say, but both GCP and AWS are really good. Try it on :D