One other idea I had for you since you claim not to mind monotony at times and do not “need” the variety, is to shop in bulk for protein. When I am visiting family they usually have a Sam’s Club membership (bulk food store). I get whatever is on sale there at the time I’m visiting. So it might be a massive amount of chicken, beef, salmon, etc but the prices are awesome. Usually I’ll buy 2 types of meats/fish. So maybe a large batch of chicken and a large bag of frozen (unseasoned) salmon filets. I’ll portion out the chicken and freeze what I won’t eat that week and then I have a large supply that I can just grab out of the fridge. I do the same thing if ground beef is on sale or even lean ground turkey. This is how I buy the majority of my meat (usually once a month) and then I just buy the staple proteins like eggs weekly.
Don’t feel a frozen salmon filet is a pain to prepare. I usually pull it out of the fridge at breakfast and let it defrost. At dinner I toss it onto my george foreman knock-off grill with some cajun/lime juice and it’s delicious. I do the same thing with chicken. I rarely sit and bake/broil meals. I just toss all my meats onto my grill and it’s ready in 5 mins.