Storing files on the API or on the microservice filesystem

I work on an app that consists of a

• Frontend app
• API, that I like to think of as a gateway
• Microservices that handle the business logic and db work

Upon implementing a file store-like feature, for uploading both small and large files, I just assumed that I'd store these files on the microservice's filesystem and save paths, along with metadata, into the microservice's db.

Because the microservices don't implement any Http API endpoints, I upload files over my API gateway. But after realizing how much work must go into transferring these files from the API to the microservice, aswell as serving the same back, I just went with storing them on the API's file system and saving the paths into the microservice's db.

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Is this approach ok?

Is it weird that my API gateway stores and serves files from it's own file system? If so, should I transfer the files from the API to the microservice, upon an upload, even considering the files can be large - or should the microservice implement a specific API itself?

I hope this question doesn't get interpreted as opinion-based - I'd like to know what approach would be best considering the frontend-api-microservice pattern and if there are any architecture standards that address this scenario, and also if any approach has it's gotchas.