I use Apache Guacamole, which works great for just about any kind of remote access and has a dead simple to use Docker Container.
It supports folders, copy/paste, uploading/downloading files, multiple open connections at once, and alternative mouse modes for touch screens. Best of all, it’s completely free and open source.
I currently run it with Keycloak for Auth and previously had it behind a Nginx Proxy Manager reverse proxy, but have since switched to using a Cloudflare tunnel.
It works great and allows me to provision limited and controlled access over various game servers to admins of those servers. They can access what they need and nothing more, and only on the servers that they have been granted access.