Web/PC interface for iPhone text Messaging
No web or PC interface are viable. 

Just messages on macOS allows a non iOS interface, however all recent iOS devices have full keyboard support. Wired and wireless keyboards work great even on an iPhone and command tab app switching lets you rock keyboard shortcuts and navigate almost everything out of the box without a touch interface. 


https://www.macstories.net/?s=Keyboard
https://support.apple.com/en-us/HT202041
Lightning to USB Camera Adapter - https://store.apple.com/xc/product/MD821AM/A


TLDR - hook you PC keyboard to your iPhone for fast messages texting and writing.