You could try just making a basic fermented dex based liquid using one of the turbo yeasts then charcoal filter it. Alcotec 24 turbo yeast claims 24% if you simply ferment at a lower temperature for a longer time up to the tolerance of the yeast, that would probably reduce any off tastes. According to their site:
The finished product, pure alcohol between 14% - 23% alcohol, can then be used as a base for mixing drinks, mixing with essences to make lower alcohol versions of many spirits...
It then goes on to describe other processes that we don't discuss here. Similarly I haven't provided a link to their site as we are not, on this forum, interested in those other procedures.