Would you need all the stripe credentials all the time (in memory)? Would you need to update them with deployments or would you need something more real-time?
Not sure if having many environment variables could pose an issue, I can imagine processes becoming heavy due to this (eg.: on fork) but I don’t have hands-on experience on a similar setup.
Furthermore, I think nowadays is not a good practice to store secrets in environment variables, some discussions in the topic:
There are many alternatives, AWS also offers some services, there is also Vault from Hashicorp, or keywhiz from square which might be better suited for this use case.