I'd like to point out that if you require offline functionality in one project that it likely isn't a good fit for your other project that doesn't require offline functionality. We all have finite time and it's great to learn something once and be able to use it multiple times.
Offline functionality naturally requires client-side code to handle storage, caching, synchronization etc, so client oriented frameworks are preferable in those scenarios. However, this comes at the cost of additional complexity, and I argue that this complexity may be unnecessary and htmx may help you achieve your goals easier
You said it yourself:
> We all have finite time and it's great to learn something once and be able to use it multiple times.
We all have finite time and it's great to use tools that help us work efficiently, following the strengths of those tools, instead of having to maintain unnecessarily complex solutions