Logic Masters Deutschland e.V.

This puzzle was created for Emphyrio as part of the 2024 Secret Santa gift exchange on the CTC Discord, and is posted here with their permission. One of their listed interests was poker, so I decided to try and create a Sudoku puzzle that incorporated modified rules of Texas Hold 'Em poker. Some basic poker knowledge is required to solve the puzzle. Estimated difficulty is between 2 and 3 stars.

Rules:
Normal Sudoku rules apply.

Green lines are German Whispers lines: adjacent digits along a green line must have a difference of at least 5.

Sudoku Hold 'Em:

-- There are 36 cards in the deck: 4 each of the digits 1-9, so among all cells representing cards, there can be no more than four of any one digit.

-- There are no suits, so flushes and straight flushes are not possible. 1s are always low, and 9s are always high. This makes the best possible hand four 9s with an 8 kicker. Within these constraints, normal poker hand strengths apply.

-- Each two-cell red line represents the hole cards of a player. The number by each line is the seat number of the player.

-- The flop, turn, and river are given by the caged values. The river card value must be determined by the solver.

-- At least two different players had three of a kind on the flop.

-- Every player had a hand at least as high as two pair after the river was dealt.

-- No two players had the same best 5-card hand after the river. The seat number also matches the relative strength of the best Sudoku Hold 'Em hand possible after the river (Seat 1 has the strongest, Seat 2 the next strongest, etc. until Seat 8, which has the weakest hand).

For some additional clarification for those who may be less familiar with Texas Hold 'Em, each player has two hole cards and there are five community cards that everyone can use. The hole cards are dealt first, followed by the flop (3 cards), then the turn (1 card), then the river (1 card). Each player makes the best possible 5-card poker hand they can with the 7 total cards available to them (their 2 holes cards and the 5 community cards).

For the purposes of this puzzle, here is a list of the possible hand types sorted from strongest to weakest. If there is otherwise a tie for something like 3 of a kind, the next highest card is used to break ties (just like regular poker):
-- Four of a kind: Four 9s is highest, followed by four 8s, etc. down to four 1s
-- Full house: The 3 of a kind is the primary value, followed by the pair (e.g., 99911 is better than 88899)
-- Straights: The highest possible straight is 56789, while the lowest is 12345
-- Three of a kind: Three 9s is the highest, followed by three 3s, etc. down to three 1s
-- Two pair: The highest pair is used first, followed by the second pair (e.g., 9911 is better than 8877)
-- One pair: Similar to 3 or 4 of a kind, ranked 9s down to 1s
-- High card: Highest card is counted first (e.g., 94321 is better than 87653)