Personally I'm splitting my category with various betting advice into ~10 categories.
E.g. Betting Mathematics. So a person who's into numbers (not everyone is) can read this cat to find out all about odds comparison, bonus EV, juice, probability and other stuff.
And I'm doing it for the sake of users.
With such specific cats, you can list them on the front page in such a way that many articles are "fresh", whereas with only one cat only the top 3-4 are and it would be a mess of topics. One of the main rules is to not confuse the user.
I'd assume Google would value a site that has specific cats more than one with one cat /betting as every single site with poor content has that.
You can't build a quality website without proper structure. Structure creates the UX.
Bet365 wouldn't get very far if they had a list of all matches without sport/league cats, or if all their bet markets were one giant sheet.
With 250 articles, you do need categories. For users, not for Google.
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