How to freeze your own produce & meals, without cell wall break down?

...far from an expert, but I think there are two issues. First, the speed with which you can get an item frozen. Quicker freezing means smaller ice crystals. I assume this leads to a reduced cell structure breakdown. LN might get you there quickly, but the item will warm up when you put it in your freezer. The second issue is, not only is a home freezer not cold enough for prolonged storage without cell structure breakdown, but it probably also has an auto defrost cycle that cause temperature fluctuation. This probably leads to additional cell structure breakdown as things warm and cool over time. There are definitely other pieces of equipment, blast freezers and super low temperature freezers, however most make little economic sense for the home.

Personally, my best success has been with vacuum sealed foods...used in weeks, not months.

I've made a comment already, but on thinking about it, I've more to say. Mostly, when you freeze foods, the cell walls are already ruptured because you've either cooked or blanched the produce beforehand. Raw meats undergo changes when frozen, but I can't speak to how much they lose nutritionally, or even if they do. Certainly, the advice to cooks regarding beef (steak or a joint) is to always freeze it before use, because it helps to break down the fibres, giving a more tender meat once cooked. Cell walls are also ruptured by slicing, dicing or cutting, and many vegetables will have been treated in such a way before freezing.

Being both a cook and a gardener, I can pass on that everyone I know who freezes runner beans (washed and sliced first) or rhubarb (chopped) does not bother to blanch before freezing, since the only advantage it's supposed to confer is preserving the colour if you wanted to keep them frozen for longer than six months. With rhubarb, I haven't found that to be the case anyway, it always loses its colour when it's finally cooked, whether it's been blanched or not.

You do need to look at cookery resource material for a fuller answer. I can tell you that certain foods keep for shorter times in a freezer than others, and sometimes that varies with how it's prepared, and certainly on whether you purchased it frozen in the first place, or froze it yourself. Industrial freezers do have lower temperatures than home ones, but an efficient home freezer is perfectly adequate for most requirements.

This may not be quite what you are asking, but you might want to check out the book The Gardener's A-Z Guide to Growing Organic Food. For every veggie and fruit in the book, the author gives recommendations on the best way to preserve. Sometimes that means freezing; other times it is drying, canning, or pickling. It really all depends. Personally, I opt to preserve using the method that gives the most flavorful results, and then I cook to the strengths of the preserved food. My frozen beans, for example, never have the lovely crisp freshness of beans of just picked, so I put them into dishes that don't need that crispness for them to shine.