The expectation level for UIs on mobile devices has been set very high. There is a lot of detail to get right in order to deliver the experience that people expect. That UI specific work is very time consuming.
It doesn't really matter what else is going on in your app, if that work can be done more efficiently to produce a more consistent result, then that's the decision you make.
> work can be done more efficiently to produce a more consistent result
Often with frameworks like React Native or Flutter, it means inconsistent UX bugs on each platform. Why do you think Facebook and Instagram and Airbnb abandoned RN in all their primary interfaces?
The "more efficient" implementation might lead to consistency across platforms, but people are pretty tied to the phones they have. Things like dropped frames, slow scrolling, UI locks, all have a subtle effect on the user whether they can point it out or not, and you're more likely to have those problems by diving in to these frameworks without understanding the underlying platforms.
This isn't argument to share no code whatsoever. But so many people who immediately turn to these frameworks either want to ship something at the expense of UX/design, their app is so small that it doesn't matter, or they have no idea what they're getting into.
It doesn't really matter what else is going on in your app, if that work can be done more efficiently to produce a more consistent result, then that's the decision you make.