At that scale the absolute cost difference is pretty small, right?
None of your dev team has a background in sys admin or managing a DB? You're going to be in for a period of difficulty while you gain those skills and that's going to be felt quite heavily on a team of 5. Now if only one of you picks up that skillset now you've also got a high Bus Factor (1) in the event something goes wrong with your self-hosted infra.
It's entirely possible that you're right in the long term but in the short term it doesn't make sense because your team is too small and the cost difference, while probably proportionally large, is almost certainly tiny in absolute terms.
I would explore the possibility that you want to be able to easily move off of Azure in the future. This may or may not be worth planning for but it likely makes more sense than going to self-hosted right now. If you can get buy-in that you shouldn't be on Azure long-term then you should avoid Azure specific services that will make it harder to switch. This would mean keeping your stack simple - compute and DB where possible. Avoiding things like Event Grid, their PubSub product and possibly even their CI/deployment offering.
Again - even doing that very possibly does not make business sense and you shouldn't approach that analysis with a specific conclusion in mind. Does your product need something like their AI offerings? If so it's probably a lot faster and more effective to lean into the products they're offering than trying to run an alternative yourself on their compute.
None of your dev team has a background in sys admin or managing a DB? You're going to be in for a period of difficulty while you gain those skills and that's going to be felt quite heavily on a team of 5. Now if only one of you picks up that skillset now you've also got a high Bus Factor (1) in the event something goes wrong with your self-hosted infra.
It's entirely possible that you're right in the long term but in the short term it doesn't make sense because your team is too small and the cost difference, while probably proportionally large, is almost certainly tiny in absolute terms.
I would explore the possibility that you want to be able to easily move off of Azure in the future. This may or may not be worth planning for but it likely makes more sense than going to self-hosted right now. If you can get buy-in that you shouldn't be on Azure long-term then you should avoid Azure specific services that will make it harder to switch. This would mean keeping your stack simple - compute and DB where possible. Avoiding things like Event Grid, their PubSub product and possibly even their CI/deployment offering.
Again - even doing that very possibly does not make business sense and you shouldn't approach that analysis with a specific conclusion in mind. Does your product need something like their AI offerings? If so it's probably a lot faster and more effective to lean into the products they're offering than trying to run an alternative yourself on their compute.
(1) - https://en.wikipedia.org/wiki/Bus_factor