Yes, the issue you're facing — font sizes appearing larger on your deployed app (on-prem Linux + Postgres) than in your local environment — is a common rendering discrepancy often caused by differences in system fonts or browser defaults on Linux servers.
Always define font-family and font-size explicitly in your custom SCSS theme.
Don't rely on system/browser defaults.
Use browser Dev Tools (F12) to inspect what font is actually being rendered in each environment.
The browser accessing your app might have different zoom level or font setting, check that also.as suggested above add CSS to enforce consistent font size.