Readability is very high prio. If only you is reading your code, I’d go for what is the most readable. But as usual, readability is very much about what you get used to…
Lambdas can be useful if you only need a simple function once.
The drawback of lambdas is that they are anonymous functions, so during debugging callstacks can become difficult to understand.
If you are in a situation where you type the same code for lambdas in different places you should create just real functions: DRY principle (don’t repeat yourself).