Barb and I do a weekly menu usually about three or four days ahead of time. That's so we can make up a grocery list and get anything we may need. We also buy 90% of our proteins on sale and store them in our two garage freezers plus we have a large pantry in the garage which we use for storing can goods.
We also make casseroles and soups and other meals that can be frozen for future meals also.
We get most of our ideas from my pandemic collection of recipes I got off the net to keep busy when I was staying home during the pandemic. That collection is around 2600 recipes in binders, so we won't run out of ideas for dinners and such.
Been doing a weekly menu now for about 20 years and it works great for us and cuts down on costs quite a bit.