I know much and all workers mined few days fine
I changed nothing
This is a pool's issue and I specified this
Sorry for too many emotions
Now I am trying to mine Verge without autoexchange with blake2s algo and speed became closer to miner reports, than in autoexchange mode

by the way, the second issue I have found is that blake2s spmod crashes, when pool asks statistics, so I disabled stats and miner began to work fine