You can disbelieve the miraculous elements of the NT and still reasonably assume statements that Jesus was from the family of David to be accurate, and therefore consistent with the genealogies. But if you think the whole NT, including the non-miraculous details is fabricated or wrong, I would suggest this is not very sensible.
You could but you would look for evidence to support the genealogies being accurate. So a good starting point would be to look for consistencies between a reported genealogy and other reported genealogies. Which of course you can do as there are two of them in the gospels - problem is that they are woefully inconsistent.
Now if you take a biased starting point (that the gospels are true and accurate) then of course you can conjure up all sorts of convoluted ways to try and explain away those gross inconsistencies.
However if you come at this from a starting point of neutrality the clear conclusion is that at least one must be wrong. Add in some non-biased rationalism and ask how likely it is for anyone to be able to accurately report their genealogy over dozens of generations (even now, let alone then) and the notion that these genealogies are accurate becomes increasing implausible. Finally throw in the notion that they are fundamentally built on a lie (or at least Luke's is) that Adam was the first human and their credibility crumbles to dust.
There is no credible evidence to support the genealogies being accurate.