The planning is harder than the actual cooking sometimes and I'm losing my mind

My wife and I started meal prepping on Sundays after our kid started daycare — weeknights were just impossible otherwise. But we realized the actual prep is only part of it. The hard part can be deciding what to make, making sure ingredients overlap so we're not buying 40 things, figuring out what to prep now vs. cook fresh on Tuesday. We've got a decent system going (plan meals → shop ahead → batch prep Sunday) but the planning piece still eats up way more brain power than it should

What does your system look like? Especially curious about:

• How do you decide what meals to make each week?
• Do you plan around overlapping ingredients or just wing it?
• What do you do about stuff that doesn't keep well — fish, citrus-heavy things, etc.?

Need to steal some ideas from people who've figured this out better than us