The most straightforward way to accomplish this within the bounds of the device would be to create a YouTube account, upload your video content there, and access via the YouTube app on Switch. Given the nature of your content however, you may want to upload the videos and mark as "Unlisted," though understand this does not provide any implicit privacy.
You have a few options you could research outside the scope of support for the Nintendo Switch:
- Install a custom firmware to your Nintendo Switch and homebrew media viewer software. This may not work on your model of Nintendo Switch. This may be in violation on Nintendo's Terms of Service.
- Install a local media server to your Raspberry Pi, a PC, or another device. The media server you install will need to have an HTTP/HTTPS access method view the content. You could then access this content via a third party DNS service that allows Web Browser access on the Nintendo Switch. Note that by using this DNS, the privacy of your Nintendo Switch's web browsing is not guaranteed.