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.
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.