Perhaps you can't decide which processor to buy, you can make a decision by looking at the Intel Core i5-9400H GeekBench 5 score multi and single core test and understand is it a good CPU or a bad one to buy, how powerful is this CPU. Here is useful information from GeekBench 5 benchmark. A step-by-step analysis of all the technical characteristics, so that it can be easier to read, is summarized in the table. After reading the results this test and video, you can already make an informed decision about do you need to buy Intel Core i5-9400H or not.
All the number that you have looked at here do not mean that you should be guided entirely by them and trust a simple comparison of these numbers. Better to watch benchmarks video and read the reviews of of people who bought Intel Core i5-9400H before making a decision buy this processor or not.