What is inferior Te *actually* about? Depending on the source is either being worried about your reputation/what others think of you OR not trusting your own competence OR feeling stifled by any sort of regulations and external criteria. I actually think ISFPs are a confusing type to identify because so much of what's said about them sounds like 4: super sensitive and artistic and *aesthetic*.
IxFPs tend to perceive inf Te as threatening authenticity and the right to be yourself. Something I've observed is that the harsh and belligerent Te is usually from people with weak Te who are otherwise unbalanced.
Te in isolation is laser-focussed on end goal. It goes by protocols, objective standards and the most efficient steps to get from A to B. Fi-dominants fear this as "erasing identity", so objective assessments of performance ends up interpreted as judgements of their character. Also believing that they have to get it perfect at the first try so end up not trying altogether since "at least" they didn't fail that way.
Fi-dominants process their environment inwardly, meaning they make value judgement of the people and the situations they encounter. Like Ti-dominants, they construct a model except theirs is founded upon notions of right and wrong, personal preferences and passions.
When ISFPs don't balance Fi by using their aux Se in a healthy way, they'll paint themself into a corner. Cut themself off from the outside world and cling to apathy which feels safe. Engaging with the outside world (Se) is needed to see whether their value judgements (Fi) will stand the test of reality. That way, they become more objective without feeling they have to give up their values.