9-34 or 9-36 vs. the standard Helix 10s 11-36 gives longer gear inches unless a smaller chainring is used.

To mount a cassette with a smallest 9t cog, a SRAM XD or XDR freewheel is needed, what means that the original hub must be changed.

Its maybe cheaper to buy a Helix Ultralight which is factory equipped with 11s and a 9-34 cassette than upgrading a standard Helix?