I think there' numerous services which would be able to host your app, I'd suggest that you need to consider a few more factors.
- Availability. Is this a hobbyist site that does not high levels of availability? Or should you be considering a HA design that spans multiple regions.
- Feature Capability. What other features of the hosting environment do you need? Static Web Apps are a simple way to host static content, but is not as feature rich as a service like App Service (eg. Slots).
- Non Functionals. What other requirements of the system do you have? Will you a Web Application Firewall for web attack prevention? Do you require private networking? Etc.
- Portability. Are you happy building for Azure services or would you prefer to select services that would more easily support a re-host? Containerising with Azure Container Apps and using the MongoDb driver for CosmosDb would likely bubble to the top as far as options go.
- Experience. What languages and Azure services are you already familiar with and able to quickly troubleshoot to expedite your development.
- Cost Predictability. Do you want predictability each month, or would you prefer the cost to be dynamic on the service usage?
- Cost - Free tiers. It's entirely possible to host using Azure services like Static Web App, Azure Function and Cosmos making extensive use of the free tiers of these services.
A long list (and i could go on!). Often you'll have a weighted requirement, and usually for me it's Experience, Cost and Portability... In that order.