Just preheat the board, get your hot air station, heat and remove those bad modules, clean the pads, add your solder and remount some new ones before cleaning up all that flux you were using. Then reinstall macOS and restore your backups.
It might take a few tries before the solder balls up correctly under each pad. Use plenty of flux. Maybe give it a ultrasonic bath.
Ah yes, Apple is known for making things obvious, intuitive, easy, and user-friendly! /s
Having an actual mini-sata or m.2 connector won't be too taxing. But it will increase tech support costs, and lower profits from sales of new replacement machines at least.
Sad. (That's why my choice is Thinkpad T series, which is built like a tank: heavy, bulky, easy to replace any part, and hard to actually break; also, enough room for a good keyboard.)
Even the XPS 13s are more serviceable than their rival MBP 13"s. The RAM may be soldered on both but the XPS uses a standard NVMe SSD. It's saved me a few times already.
It might take a few tries before the solder balls up correctly under each pad. Use plenty of flux. Maybe give it a ultrasonic bath.
Source: YouTube