This sounds more like the infamous post-covid loss of taste / smell. To my knowledge, Lucas has never complained that foods don't taste as they should, he just likes mixing together foods that objectively DON'T go together. And its certainly not the result of a dental procedure: his last dentist visit had to be with or before Suzanne, and evidence suggests Lucas has ALWAYS been this way about food. I would even bet that his ego about his own cooking stems from his parents thinking it was cute that lil' Lucas liked to mix together disparate ingredients, and told him he was a little chef. He's so proud of his culinary creations; he MUST gave gotten reinforcement about them at some point.
I appreciate the medical insight, (never heard of dysgeusia) but I dont think its quite the same thing. This is a bigger problem than dysgeusia. Something's wrong with his brain in the area of food pairing. Popcorn on pasta? Thats more of a textural abortion, but ok. Raw green beans and pepperoni in an uncooked tortilla? Mustard on a protein bar?
Its not as though lucas is simply using what he has on hand, and because of a lack of ingredients, is forced to try strange combinations. Rather, he has actually gone out and bought these bizarre incongruous ingredients for the express purpose of crafting these nauseating "dishes".