I had a similar problem with low overnight sugars so I'll describe my solution in case it sheds some light on your situation.
I was on a long-acting basal dose taken at night, and rapid-acting mealtime doses, however the basal dose for stable daytime sugars gave slightly falling overnight blood glucose, and the problem had been getting gradually worse over a period. Although I always test at night and kept my sugar high before sleep, adverse events sometimes magnified the overnight fall and led to recurring early morning hypos, sometimes severe.
The solution was to split the late-night basal dose into morning and evening doses, 12 hours apart. A 2/3 am and 1/3 pm split now gives me stable fasting glucose levels, suggesting that in my case most of the effect of the ultratard is quicker than the manufacturers suggest, and quicker than when I started on this regimen.
Of course glucose levels can still be thrown off by exercise, illness, meals etc, but it's a lot safer than it was, and although I would much prefer continuous monitoring, I am able to use my standard meter.
The other point I would make is that it is possible to calibrate carbs very precisely with scales and a calculator. Packet bread is labelled with the carb content, and most plain breads are very similar being mostly flour, if you buy loose rolls from a baker. In the old days on a short and medium-acting mixture when the dosage couldn't be adjusted to meals, I weighed everything and ate exact amounts of carbohydrate at different times of day. As long as other things remained the same - exercise, health etc, then it produced very consistent results.
These days things are much easier, but the flexibility of rapid-acting insulin introduces variation in dosage which can be tricky to control. And all the other things you mention continue to knock things off course. However carbohydrate intake is quantifiable when you eat at home and potentially more stable than most of the other factors which affect blood glucose. It sounds like you are taking rapid-acting insulin, but if you are taking a mix of rapid and longer acting then that suggests controlling it tightly with constant doses and carbohydrate intake. Or discussing whether a different regimen would give more stable overnight sugars.
If you haven't had the opportunity you might be interested in the DAFNE course which my brother - an impatient long-term diabetic - found very helpful. On the other hand you may have already figured out what they're teaching.
Apologies if this is off-topic for you but hopefully some of it is relevant.