The other rule that fixed most of my flat results: not everything goes in at the start.
A recipe written for ninety minutes has one timeline. Stretched to eight hours, ingredients that were meant to keep their character are destroyed. What suffers:
Dairy. Cream, milk and yoghurt separate over long cooking. Add at the end, off the heat if possible.
Anything green or delicate. Peas, spinach, courgette, fresh herbs. These want the last few minutes, not the first eight hours.
Seafood. Minutes, not hours.
Pasta and rice. Cook separately unless the recipe is written for it, or you get a starchy mush that also thickens the sauce in a way you did not choose.
Fresh herbs, citrus zest, garlic you want to taste. All flatten out completely. Dried herbs at the start, fresh at the end.
What genuinely benefits from the full time is the tough cut, the root vegetables, the dried beans and the pulses. That is what the machine is for.
So the honest answer to your last question: most dishes do translate, but the conversion is not one adjustment — it is less liquid, brown first, hold back the delicate things, and finish with the lid off. Do all four and the gap between the two versions mostly disappears.