If we should not give any weight to Einstein's opinions on epistemology, why should we give any weight to your opinions on Einstein?
You should not, any more than I give any weight to yours.
However, that does not deny me the right to have them.
Where Einstein made remarks about things other than physics we ought to examine his supporting arguments as closely as we would examine anyone elses. Since this is the internet no-one's credentials can be examined so everyone's argument is worth as much as they are prepared to back it up with facts, checkable references, and manifest knowledge of what they are talking about.
To give you a more serious reply:
Since science has nothing to do with metaphysics
(words to that effect you have posted several times)
and since you cannot have epistomology
without a metaphysics
(at least as a subconscious substratum)
it logically follows
that a man's background in science
however eminent
does give weight to his thoughts on epistomology.