Actually this is not an answer, more like follow up question (because I've yet to have reputation to put up a comment on the highlighted answer).

I also happens to be in a similar situation with you, I basically create a Linux-based image Azure Http Trigger function and wants to deployed it into Azure container function.

May I know how do you deploy the function? Which method/type of azure service did you use?

As for me, I've been trying using the az cli command like this below but so far been unsuccessful and still gets 404 for my endpoints.

az functionapp create --name MyFunction --storage-account StorageAccount --resource-group MyResourceGroup --consumption-plan-location regioncode --image dockerId/functionRepoName:vTag