This is 1/2 the price.
https://www.amazon.co.uk/Adrawpen-Re.../dp/B09G5R9YJZ
I'd not recommend it as there is no assurance about quality or compatibility.
The Kobo stylus is fine in my tiny hands and less diameter than many ink pens or art markers or brushes.
Obviously you can buy & use whatever you want, but for this type of application the rechargeable solution and zero assurance of how compatible it is at the similar price isn't an educated recommendation. I've designed this sort of stuff for a living and had an electronic pen patent. It's for a Microsoft surface.
Personally if I need a replacement or a second stylus so as the Sage & Elipsa can be used by two people here I'd buy the Kobo one. If a much cheaper one is actually advertised as Sage or Elipsa compatible I'd consider it. But I'd recommend people should be wary of buying 3rd party stuff at the same price as official with NO mention of compatibility.
You've just been lucky and the replaceable cell in this is not like a battery for a torch or toy car. The rechargeable cell does a fixed number of cycles. It it even replaceable?