SharePoint OnPrem limitations

our client is using SP 2019. We are designing custom solution for them on SPFx.

The latest version of SPFx that we can use is 1.4 of course and react latest supported is 15 so react hooks are not supported.

Also we cannot use latest version of PNP JS.

All latest fluent UI react components also uses react hooks so they are also ideal for SP Online.

Also you cannot use latest validation libraries like react-hook-forms for form validations that you do for SPFx forms (again because they use react hook which can't be used on onPrem).

if only latest version of the react is made supported in SPFx 1.4 or latest SPFx is made to support then there is hope.

What is the solution for onPrem in that case to above limitations.

Is there a user voice thing for SP OnPrem that we can raise?