I'd disagree. In some/many cases the subconscious may well suppress data that do not fit the solution or theory we have already clung to.
I think the Freudian "subconscious" is by now discredited. Ego, superego, id were unscientific concepts. The modern approach is to study the brain. Scans of the brain show activity in various areas, at low levels. When an activity flares up and lights up the whole brain in a certain way, it enters consciousness. There is no concept of suppression. No concept of clinging to a theory.
There is a well documented and long known experience in mathematics research. You have a problem, say a result to prove, which you have a hunch is true. The conscious brain is not too good at this sort of thing, it can do the logical bit but is not good at finding new solutions and is incapable of parallel thinking to investigate all possibilities. However, the brain itself is highly parallel as a computer, and most of its activity never even enters conscious thought.
Mathematicians have long reported that after failing in a proof, then sleeping overnight, an idea of a solution pops into their conscious thought. (Or an idea for a disproof of what they thought was true.) Their brains have been working in the background and exploring possibilities, until at some stage one takes priority and causes this flaring up of total brain activity, the precursor of the idea flares into conscious thought.
Of course, the conscious thought processes, which are quite pedestrian, then have the task of filling in all the details of a proof.
So, I don't think there is any real bias in what the brain does in the background. Einstellung makes it appear as though conscious thought was all powerful. What we consciously become aware of is a tiny fraction of what the brain is working on. Einstellung is based on an outmoded approach to how the brain is now known to work.