Currently the "Premium" tier on App Service offers this three options:

P1: 1VCore DSV2
P2: 2VCores DSv2
P3: 4VCores DSv2

I wouldn't call this a premium tier now that we are getting into 2020...

App service is one of the most useful services offered in Azure and it really needs an upgrade.

Amazon's Beanstalk does not have such limitations.

I would suggest that to upgrade the hardware/resources of the Premium tier to at least:

P1: 2 VCores
P2: 4 VCores
P3: 8 VCores

The processors model should be upgraded as well to use DSv3 or even better the F series.