I tend to do a big shop in Morrisons every fortnight then a smaller top up shop in Aldi or Lidl the week in between. I tend to prefer Aldi to Lidl for most things especially as my local Lidl often has bizarrely empty shelves (even pre pandemic).
Lidl do great cooked meats as someone above has said, I love their smoked turkey or smoked chicken and their smoked cheese. I've also just discovered their pink grapefruit gin in a tin for only 89p
In Aldi I like their Greek yoghurt, sweet potato pakora and falafels, chilli lime and coconut sliced chicken, cappuccino and latte sachets, their knock off Twix and Mars (Jive and Titan bars), knock off Biscoff spread and their Mediterranean light tonic. Also love the super 6 fruit and veg offers. The Specially selected sourdough pizzas are fab and much nicer than Pizza Express (actually Lidl posh pizzas are also fab, I suspect they're made at the same factory as the flavours are similar). Their Rose Glow skin tonic is a great dupe of the equivalent Pixi one which is £18. Aldi are buggers for discontinuing things though, eg I was in love with the rhubarb tonic water but it's just been discontinued, and they used to do these fab mini goat cheese pearls that had a longer shelf life than a normal slab of goat cheese and were great for pimping up pizzas but they only stocked them for a short while.