Best way to handle large file uploads

[iggy]

I've been using echo/oapi-codegen for a pretty simple API I wrote to handle managing a package repository. Basically it just takes uploaded files and puts them somewhere in a filesystem. I've noticed recently (I don't think anything changed code wise, I think my upload file size just reached a tipping point) that my API is consuming a lot of memory and subsequently gets killed by k8s. The file that I noticed this on is 1.5GB. When I try to upload it, the API ends up using close to 8GB of memory. I've tested enabling h2c, upping the read frame size, etc. I also tried a couple older versions to see if any code changes caused it and it doesn't seem to have. I normally run this behind a reverse proxy in k8s, but I've been testing locally on my laptop, so I don't think there's any sort of network latency/etc that could be causing issues.

Any thoughts on things I could try to narrow down what I'm doing wrong?

For reference, here is the API code:
https://github.com/atlascloud/packages
Server init:
https://github.com/atlascloud/packages/blob/main/cmd/api/main.go
Upload function:
https://github.com/atlascloud/packages/blob/main/internal/openapi/packages.go#L120
(I also tried stripping everything out of this function to the point that it was a debug log and a return line with a hardcoded string)