I am just a hobbyist programmer, but asking to implement a linked list, IMO, is like asking to build a hammer - harvesting the wood for the handle, smelting iron, etc. We know what hammers look like and do, they haven't changed much in millennia.
I'd move the questions up the level of abstraction, as in - given this problem, how would you solve it? You have access to a hammer, a drill, a rotary tool. Solve it using any one tool or a combination and then explain why you chose that tool.
Depend what your company actual does. More relevant tasks I have seen involve 2D arrays or transforming data from a Python dict, or parsing JSON. The idea is to test the ability to understand and manipulate complex objects, which is a good generic bar.
I'd move the questions up the level of abstraction, as in - given this problem, how would you solve it? You have access to a hammer, a drill, a rotary tool. Solve it using any one tool or a combination and then explain why you chose that tool.