1. Colour 9 cells in the same grouping. I chose the cage stretching from r4c8 to r8c4, on the grounds that 8 of the 9 cells have a palindrome line passing through them.
For convenience, I'll refer to them by letters: A = r4c8 (red) B = r5c8 (gold) C = r6c8 (pale yellow) D = r6c7 (light green) E = r7c7 (dark green) F = r7c6 (light blue) G = r8c6 (dark blue) H = r8c5 (grey) I = r8c4 (pink)
2. Fill in the palindrome pairings A : r2c5 B : r2c3 E : r5c9 F : r4c9 G : c6c1 H : r5c1 I : r7c3
3. In box 9, F can't be in the big cage (because of r4c9), and it can't be in r7c8 because then it would also have to be in r6c9 F : r9c7
4. Fill in box 6 I : r5c7 (can't be r4c7 because r1c4 conflicts with r8c4, and can't be r6c9 because r7c8 conflicts with r7c3) G : r4c7 (r6c9 conflicts with r6c1), so r1c4 also H : r6c9 (by elimination), so r7c8 also
5. box 5 G : r5c5 (and it must be the digit "9", because the hop box logic requires 1-8 to be in the other spaces in order to allow knight moves between them.)
6. Follow on from that G : r2c8 (because r4c7 is already in the big cage, and r1c9 conflicts with r1c4) G : r3c3 (only remaining possible place in the cage stretching from r2c6 to r6c2)
7. Box 1 H : r1c2 (only place left in box 1 that isn't in the cage)
8. Box 4 D : r4c1 (r4c2 and r5c2 would conflict with r1c3 because of the palindrome) B : r6c2 (similar reasoning) I : r4c2 (only place left for it, because of r7c3 and r5c7)
9. Follow on from that I : r3c1, r1c5, r2c9, r9x8, r6c6 E : r3c8, r1c6 F : r1c8
10. With E now ruled out, r1c1 can only be an A A : r1c1, r6c3, r8c2, r9c6, r3c7, r7c9, r5c4
11. Fill in the rest of the colours E: r2c2, r4c3, r9c4, r8c1, r6c5 etc.
12. Hop Box B : r4c4 = 1 E : r6c5 = 2 H : r4c6 = 3 A : r5c4 = 4 I : r6c6 = 5 C : r4c5 = 6 F : r6c4 = 7 D : r5c6 = 8 G : r5c5 = 9
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SudokuSolves/RegionalConflicts