Actually you just described a front-end developer, which I guess you call "UI Development". Which is really a scam by companies to overwork one individual with

Actually you just described a front-end developer, which I guess you call "UI Development". Which is really a scam by companies to overwork one individual with two jobs. UI and actual development should remain separate as there is a seriously massive workload for each. These "full stack" roles only make sense extremely early on in the company or on a greenfield project, anything where iteration and field testing take priority by virtue of simplicity as a result of time.