the golden standard for figuring out food sensitivities is still an elimination/provocation diet.
a place to start might be something like dr. k's gut healing protocol. if you don't heal your leaky gut the offending proteins will keep seeping thru the gut wall to where they're not supposed to be. also babies have leaky guts by design, so if you're eating things that your baby is sensitive to, and it's getting thru your gut, it goes into your milk and your baby will also be exposed to it. fun hey!? https://drknews.com/autoimmune-gut-repair-diet/
another thing to consider is that if you're sensitive to something like corn, and the beef that you're eating is being fed corn, then beef could show up as a sensitivity because of the corn, not because it's beef. so if you eat food that's eating what it should be eating, you may be able to expand your repertoire a bit. ie wild fish vs farmed fish, grass-fed vs cafo, etc.
headaches are a classic sign of not getting enough electrolytes while doing lowcarb, it could signal that you need more potassium, salt, calcium, etc
how is your milk supply? i was lowcarb throughout my last pregnancy and it was the best thing ever for the extreme morning sickness that i get, but i was unable to keep up my milk supply and eat lowcarb. it didn't take that many carbs for me to keep lactating properly, but i definitely was out of the range of ketosis. that's a ymmv type of thing though, there are plenty of women who are able to eat lowcarb and breastfeed at the same time. there are quite a few keto pregnancy/breastfeeding groups on facebook
re this: im not bored but i do find i have almost 0 convenience foods whch means i miss a lot of meals.
can you make extras when you're doing food prep so that you have leftovers that are easy to heat up. diy convenience meals. my family can't eat gluten/dairy/artificials, so basically everything that we eat is from scratch. i always batch cook and freeze extras so that there is always something easy to heat up.
re sensitivity to eggs: try eggs from chickens that are fed non-gmo/no-soy feed. also try quail or duck eggs, etc. i feed our chickens a non-gmo feed that is mostly pea protein instead and the eggs are soooo much better than when they're on regular conventional feed.