What surprises me after watching 600+ episodes is that police fail to see some obvious evidences like smudged blood stain, bullet casing, etc

Yeah, it was stupid. It feels like they are purposely doing it to emphasize the detectives' intelligence.

exactly!

Exactly that was the author’s intention

Well they are stupid and conan is pretty much there to solve the case

Osamu Kenzaki appears four times, twice on tv and twice in a real case. I love how the makers of the anime kept things like these consistent throughout the entire anime

Nice of Hubuki Subs to put Japanese subs in the corner there! Good reading practice for kana and kanji!

Yup

Furuya Wataru?

the killer is the one leaking the contents of the chest to the champion.

I wonder why the chef wasn't considered a suspect given that he benefits from knowing the ingredient beforehand. I know that this show only has 3 suspects max, but I thought he would be one of them. He had a motive too.

yes the challenger chef would have a motive. increased publicity, show appearance fees for the next taping, maybe there's even a cash or merchandise price etc. the champion would have the same motives.

but there are two problems with your hypothesis.

1 the challenger AND the champion i would imagine are busy doing REAL business. remember, Sonoko or Ran mentioned the champion was opening another (meaning he already has at least one) store/restaurant and it was NOT in Beika City. the challenger probably has their own full-time job placed on hold for the appearance on the show.

2 the TV STATION STAFF WOULD THINK OF THE CHAMPION AND CHALLENGER FIRST!! IN PREVENTING ANY CHEATING! i would bet the two chefs aren't allowed to even enter the BUILDING, let alone the studio until the day of the taping. at that time the show's Producer would already have his lock on the chest and it had already been returned from the Food Coordinator after he removed his lock.