Are you able to get blood tests done ASAP?
It would be a good pointer, especially on Thyroid issues which is the driver of metabolism.
Also you’re only 128 lbs - why are you trying to lose weight? To be fair, you don’t look “skinny”, there is muscle definition at least. But lower muscle mass plus short-term calorie restriction = slowed metabolism, long-term fat gain and more health issues.
I think you’re doing some of these, but record other health markers each day, like how many times you urinate, how easy your bowel movements are, your general mood, your sex drive, recovery from trianing, sleep quality, and temperature of your hands, feet and nose (slower metabolism normally leads to cold extremities for a number of reasons, including Cortisol/Adrenaline production which breaks down muscle mass to create sugars for the body to survive on).
You should be able to lose weight at 22-2400 calories per day.
To me your comment “this Soylent regimen is consuming some of my self restraint reserved for coffee control” is a bad sign. It measn you’re not giving yourself enough calories to produce energy, and the body is signalling you do do something to create energy. Coffee can increase adreneline/cortisol production which will waste muscle mass and make sleep worse, especially with insufficient sugars.