No values displayed, design is incorrect overall. Slow.

Design is totally not correct. X-axis labels, Y-axis labels are missing.

— Very unresponsive left and right handles of scroll indicator (probably because tap area is too small)
— Night Mode is absent
— Wrong design of pie chart (see screenshot)

Does not support iOS 8. Telegram does.

Major issue: does not support iOS 10.

Critical issue: This code uses Metal and it will never work on 32-bit devices (including iPhone 5 on iOS 10.3).

Critical issue: Line joints are not rounded, even on iPhone X. So, it's not some minor optimization for old devices, rounded joints implementation on Metal require a lot more math to implement, a lot more vertices to calculate for each frame and 2-3 times more polygons to draw.

Major issue: It's not so easy to port this code to iOS 8 on iPhone 5S either, because he uses help classes from MetalKit (otherwise he would support iOS 8). And you have to do a lot more work without it.

Critical issue: line drawing quality is poor. It is not easy to implement good line quality on bare Metal, MSAA is not enough. Qualitative line drawing requires a lot more calculations and tricks. And such implementations may still be worse than Core Animation / Core Graphics quality and would definitely affect the performance. You can read more about line quality in Metal projects in my comments on entry228.