This world championship says nothing about the playing strength of the engines. I'm sorry to say but Powerfritz 18 is one of the weakest engines I've tested. It's the world champion 2022. Am I unfair in saying that? See above, Stefan Pohl's ranking. A world champion in the no man's land of the table.
The fact is that the books play a big role. If I were to take Fat Fritz 2 today and play it on PlayChess (with my own tournament book), I don't think I would lose a game.
As for Stoofvlees, this engine plays much more heavily on GPUs. The Software World Championship failed to show how well this engine can play.
[pgn][Event "Round 6: Stoofvlees - Arasan"]
[Site "
https://lichess.org/study/gCgPqzgv/onqOQHbR"]
[Date "2023.07.13"]
[Round "?"]
[White "Stoofvlees"]
[Black "Arasan"]
[Result "1-0"]
[UTCDate "2023.07.12"]
[UTCTime "15:33:18"]
[Variant "Standard"]
[ECO "A01"]
[Opening "Nimzo-Larsen Attack: Modern Variation"]
[Annotator "
https://lichess.org/@/bigarrow"]
1. b3 e5 2. Bb2 Nc6 3. e3 d6 4. Nf3 g6 5. c4 Bg7 6. Be2 Nf6 7. d3 O-O 8. a3 Nd7
9. Nc3 Nc5 10. h4 h5 11. b4 Ne6 12. g3 Ne7 13. Bf1 f5 14. Bh3 Bd7 15. Qe2 c6
16. Qc2 b6 17. a4 Rc8 18. Rb1 f4 19. gxf4 exf4 20. Bxe6+ Bxe6 21. e4 Bg4 22.
Ng5 Bh6 23. Ba1 Bxg5 24. hxg5 Rf7 25. Qb2 Kh7 26. Rh4 Qd7 27. b5 Qe6 28. Ne2
Bxe2 29. Qxe2 f3 30. Qe3 d5 31. Bf6 dxc4 32. Qxf3 Kg8 33. Qh3 Rxf6 34. gxf6
Qxf6 35. e5 Qxe5+ 36. Re4 Qf5 37. Qxf5 Nxf5 38. bxc6 cxd3 39. Rc1 Rc7 40. Re8+
Kf7 41. Rd8 Ke6 42. Kd2 Ke7 43. Rxd3 Ke6 44. Rd8 Ke7 45. Rg8 Kf7 46. Rb8 Ke6
47. Rb7 Kd5 1-0[/pgn]