Pretty straightforward really. SocketInteraction is missing default values on various arguments on all overloads of RespondWithFileAsync and RespondWithFilesAsync, meaning either a cast to IDiscordInteraction is required (to use the interface's defaults) e.g.
((IDiscordInteraction)Context.Interaction).RespondWithFileAsync(fileStream, fileName)
or manually specifying all parameters e.g.
Context.Interaction.RespondWithFileAsync(fileStream, fileName, null, null, false, false, null, null, null, null)