I didn’t notice anyone recommending disposal of the LPs as trash or gifting them, but perhaps I have not read the whole thread. In the US, it could work out OK to donate them to a charitable organization and take a tax deduction. I have no idea of the tax laws in Russia. Sure, the OP could go through the collection and keep for himself anything he likes. So far, after X years of storage on his property, it does not appear he has done that. Anything he does now is justified and better from his point of view than what went before. By the way, although I have not discussed the issue with my wife, I plan to suggest to her that she should sell my LPs to a bulk buyer, likely to be a dealer. Or donate them to a charity. She won’t need the money, and I cannot imagine her or our sons selling them piecemeal.
I recently checked again the current auction finals on popsike.com for some of the records from my collection, for many Soul 45s from the 60s and 70s, purchased by me probably 15 years ago, the current prices are simply insane! I often see a typical $300-500 price tag per record when they are sold, here is one of them - this is what I call rare records.
My point is that sometime there might be 1-5 records that cost more than entire collection! Do you think the dealers will tell you that ? :)
P.S. I doubt that record collectors will tell a girlfriend (or wife) how much they paid for stuff they really want. And believe me they pay a lot for rare records. Prices go up every year, but at the end of the day there will be a dealer from the local shop (You die, We buy) with a typical offer of $5 per record for the entire collection and the wife will be like "yeah, fair price" :)