Enforce one field based on another - kebab-case example

I am using subscriptions, and it seems lambdas do not support subscriptions. I sort of understand why (since one field basically equals a function), however, this is NOT my intended functionality.

I do feel lambdas should be added to subscriptions, but I digress…

I want to actually put data in the field, not run a function call every time the field is read.

Is there a way to set the field Post.nameKebab when a new Post is created? My goal here is to prevent a front-end user from setting this field when a new Post is created.

Thanks,
J