Congratulation on completing treatment.
I hear ya, being a chowhound myself. It takes time, and lived solely on canned nutrition or farina, eggdrop soup for a long time. Your appetite, and eating ability should start coming back once any mucositis, saliva production, taste buds, and nerve response to any damage done by chemo and radiation is partially or completely resolved, which I found some to be about the 3rd month post treatment, but not 100 percent back pre-cancer, and some do take longer, and never really resolve completely like dry mouth. I still have problems with salt, sweet, and work around it, but I eat everything..steak, bread, pasta, pizza...and can taste it.
There are ways to improve saliva, so improving that will improve taste. Treating mucositis, thrush, dry mouth will improve taste. Zinc may help improve taste, drinking lemon water, smelling lemons, citic candy drinking water before meals, chewing gum improves saliva, Milk coats the mouth and replicates saliva.
Taste involves more than just tasting. It also invoives sight, smell, hearing, texture, and memory to fully taste. I try to incorporate all this, and all the tastes buds by trying as many flavor as I can...salt, sweet, sour, bitter, umami to help. One day you may even want to go to a lunch buffet to try what you can eat, it may be cheaper. Plenty times I made a complete meal, and just threw it out cause I couldn't eat it yet.
There are prescription meds, OTC products that help improve appetite....Marinol, megase, corticosteroids, anabolic steroids, caffeine, wine, melatonin to name a few, but check with your doctor.