Photos look terrible when exported!

The windows calibration is useless especially on a wide-gamut display. You need to use actual calibration hardware such as Spyder Pro, ColorMunki, etc.. This is essential for digital photography. Most schools will have one and local photo clubs often own one to borrow out to members. Libraries also sometimes have one to borrow. You can sometimes get away with the manual calibration by comparing reference files to prints of those files but this is a hard manual process. Point is without hardware calibration you can never be sure that what you are seeing is real.

What are your export settings? How are you viewing the export? If you use color managed viewers, the exported images will look identical to what you see in Lightroom and will look good everywhere even if you don't export to sRGB (which is still recommended but color managed viewers take care of that). If you see large color shifts, you are not viewing the images in a color managed viewer. Also, make sure your jpeg quality setting and resolution are high enough. The default quality setting is too low. You also need a large enough size to make your images not look blurry. 

One thing to realize is that you cannot ever trust the color you see on any phone. None of them are well calibrated. Apple's phones are slightly better calibrated than anything else but only if you turn off all the automatic modes (night shift, true tone, etc.) as they all mess up the color. On a desktop computer, you can only trust the color you see if you calibrate your computer using specialised hardware. It is basically impossible to trust the color otherwise and if your computer is uncalibrated and you compare to a phone, you will always see different color. Even worse, since the overwhelming majority of other people have uncalibrated screens, they will all see something different than you. This is an unfortunate reality of digital imaging. Best thing to do is to calibrate your own screen and export onlty to sRGB files. If you put a phone/Pad in the mix, be wary of most Android devices and for Apple devices turn off all the automatic screen modes. 

If you are dealing with noise reduction and sharpening, only look at your image at 1:1 zoom while changing settings. Ignore what it looks like zoomed out as you simply cannot judge the display in any piece of software. This is especially true for high ISO or otherwise noisy images that need a lot of noise reduction. Only way to judge what the noise reduction is doing is to zoom into thee pixel level.

The second image looks way better in my opinion. The noise reduction looks very artificial in the first. One of the things to look out for is that the noise reduction in the zoomed-out view is not accurate. You should only judge the noise reduction and sharpening settings while zoomed in to 100% which on the phone you do by double tapping. Never try to adjust noise reduction while zoomed out. This is true in all digital imaging software and is caused by the scaling down to screen size.