Finally solved the kata.
I think what is great about this kata is that it is a problem which is
very near/close to development in the real world.
E.g.
Users have their take on what the program is suppose to deliver.
The architect or business analyst drafted specifications which are somewhat conflicting or unclear.
The codebase by the developer whom you are taking over from covers most of the requirements.
But for the remaining requirements, it is a nightmare to modify the code as everything is spaghettied together.
In the end you need to craft your code to be modular and adaptible to able to
satisfy all the conflicting/unclear requirements.

The users, architect, BA and former developer in this kata are,

1. rules
2. Comments and questions in the discourse
3. The ruleset inside the rules (Texas holdem)

This answer from poker.stackexchange indicates that [Ace 2 3 4 5] is considered a straight in texas holem.
https://poker.stackexchange.com/a/4351
For my 2nd question suit vs suit, in reality with texas holem rules it's impossible to have
flushes of different suits in a game. This is due to the 2 cards each player has
and the 5 community cards. This combination cannot give rise to opposing suit flushes.
But as this is a kata..

F#. Regarding the rules:
"Low aces are NOT valid in this kata" -
Is [Ace 2 3 4 5] considered a straight hand or a high card hand?

"There is no ranking for the suits" -
Does this mean that [King♤ Queen♤ Jack♤ 10♤ A♤] vs [King♢ Queen♢ Jack♢ 10♢ A♢]
result is draw? Or Spade♤ suit wins?

I think the cache is not utilized at all. Noticed when inserting print statement inside return cached value block.

Magnifique!