Using Linux servers (which have only IP-address) and not cloud storage with Botpress text-to-speech, requires that you have a website with SSL certificate (https), because Axios cannot receive data from http (at least not in my experience). So to get SSL certificate for a server I use Let's Encrypt and build it. Problem with SSL certificates is that you cannot have it so easily to a server IP-address, you have to have a domain name also. So I just bought some domain name, connected that to my servers IP-address (all that they have in their tutorials, maybe AWS has similar instructions) and then text-to-speech works with Botpress. So I think everything else OpenAI related also works.
Using AWS cloud storage, if you can connect that to Botpress to receive all the data, might be easier way than my server-only solution 💡