Which is better

[Tenori Tejima]

The first is lineart I made at work using regular pen. The second is what I would call a very haphazard "one thickness" lineart using a VEIKK drawing tablet, with one color screentone shading. I'm confident the second one looks better on mobile phone, but that may be only because there's no small and detailed long-shot panel.

[Suuper-san]

As I'm sure you realize, "better" is quite a subjective word. It depends a lot on what you are aiming at in the first place.

I find that the two pages are difficult to compare as the composition and rendering are different as well as the style.
The first one, you haven't used any tones, and there are larger areas of white, and what seem to be missing parts of lines? the gaps are quite big in some places. There's also missing panel lines which is super confusing.
Whereas the second one uses more tone/shading and the page is full of detail, so it looks more complete as a manga page.
At a simple glance the second one looks a better manga style, but I think the first one doesn't look finished and so it's not quite a fair comparison. The level of detail in the first one is much higher in the face and texturing, and so if that was a finished page then I think I would prefer that one.

I can't say I can read manga on my phone at all, it's not the correct size for viewing pages for a start, and so if you are planning on publishing your work digitally, then a manhua style might suit you even better.

As a final thought, I would say the art style is less of a worry compared to actually producing the work, so I would say whatever style is easier to work in, is probably the best one.