Sometimes lunch is grabbed, not made. That does not mean it has to taste sad. A jar of pickles is the fastest upgrade.
Add piccalilli to ham, cheese and chicken sandwiches. Add brown pickle to anything with cheddar. Add gherkins to tuna or deli meat. Add achar to wraps, rice bowls or leftover meat.
If you keep one jar in the fridge and actually use it, your lunches improve instantly. It is a small habit with big results.