I would not recommend that overall unless it’s ultra high DACs (which you note at the beginning). Even then I would not go before 2010.
Below $3k range (approx) DACs released after 2015 (approx) solved a number of electrical distortion issues present in the electronics of DACs and we started seeing more R2R DACs.
DAC released after 2015 (approx) sound much better than older DACs.
“Vintage” DAC should not be a thing. Immature tech per my listening.

