Making high-quality frozen-food at home?

Flash-freezing equipment wouldn't hurt, but for the normal home cook, the main things are to chill it as quickly as reasonably possible, package it with as much air removed as possible (vacuum sealers help here) in individual meal-sized portions, then freeze.

Thaw in the fridge if possible, or by heating your vacuum-sealed bag in a water bath. (Microwaves are pretty bad at heating frozen blocks of food and even with a lot of attention paid will tend to overheat part while other parts remain frozen.)

Choose recipes that work for the equipment you have, and adapt your weeknight process to combine the frozen ingredients with fresh ones.

Soups, many sauces, chilis, beans and rice dishes freeze well under normal home conditions, as do some meat preparations (the texture can change, and usually, the larger the cut of meat, the more likely it is that the change from freezing will be negative). Without flash-freezing, foods with a high water content tend to become mushy, so that the broccoli you steamed to perfection will most likely thaw out to be limp and potatoes may be mushy.

Flash-freezing is a large part of it. Being somewhat energy/equipment intensive, it's hard to imagine a good "home scale" approach to that (well, I can imagine a Dewar of liquid nitrogen, but I'd find it hard to justify the expense of keeping it filled for improving one's home-frozen meals.)

You can purchase "laboratory freezers" that will hold -70C or even -150C, but they will be expensive to buy (low volume production) and expensive to run. Depending on model they may not deal well with quickly cooling to those temperatures (rate of cooling may not be as high as in needed, even if ultimate temperature is cooler than needed.)

Since you seem to be nibbling around the edges of "and turn that into a business selling frozen food" you have:

1. first, the need for a commercial kitchen, with all appropriate licenses and inspections. In most places you cannot cook commercially out of "your home kitchen" and need a second kitchen just for the commercially prepared foods.
2. second, the need for salespeople.
3. third, the need for distribution. Refrigerated warehouses, refrigerated trucks, etc.
4. fourth facing previously established competition.

I make great sorbet. I don't even need a flash freezer, it being a frozen product. I'd more than likely go broke trying to make a commercial success of selling it (and I might grow to hate making it, too, especially if I was losing money to do so.) I much prefer to have a hobby I enjoy than a business I might end up hating. I can afford to lose money at the scale of the hobby (or even consider "saved money .vs. buying commercial product" and call it a win some days.)