Beeby finds S5 naked single in the bypass, but that requires unproductive number scanning. Naked singles don’t escape Sysudoku Basic.
This one shows up in line marking,
when r9c4 sees 4 and 9.
After line marking, with r5 completed,
A hidden unique rectangle emerges. If 4r24 were true, the slinks would carry 6 to adjacent corners, forcing 4 to the opposite corner.
A boomer turned ANL removing 2r8c8 is extended to an ANL (red) removing 4r1c6. Then an ANL (green) removing 4r2c5 for N69, r2s24, N4 and C4.
Adding the blue/green cluster, 4r6c3 exits by the trap, or by the finned 4-wing.
It takes an AIC ANL to remove 2r1c7, and
to wrap green, for