I believe it is important to look at test coverage at something that
Needs to be adjusted as features grow and change (proactive)
as opposed to
Ensuring that things that happened in the past are prevented (or at least detected) by adding tests for them (reactive)
The problem with the second approach (particularly common in traditional waterfall and ...
As testers we won't set hard boundaries for testing, that's why organisations push for test automation, CI/CD and so on. We expect to get 100% (almost) test or feature coverage for each new build.
But if you are in an organisation that doesn't have test automation then some times test completion deadlines could make you feel challenged. In such cases, few ...