Hallo Jan,
On the face of it, it looks like your ancestors migrated during the 5 year reign (1796-1801) of the well liked Russian Emperor Paul and his 2nd wife Princess Dorothea of Wuertemberg. Whilst acknowledging your quest is rather like searching for a needle in a haystack - maybe the first places to look in the telephone book for descendants is from the following three areas?
...Catherine The Great, Empress of Russia 1762-1796
(born Sophie Augusta Frederica of Anhalt-Zerbst was born on 21 April, 1729 in Shtettin and died on 6 November, 1796 in St. Petersburg.) She was descended from the North-West German noble family.
Catherine invited to Russia German colonists promising them defence by law, freedom of faith and tax benefits.
When her son Paul was old enough Catherine arranged a marriage with Wilhelmina of Hesse-Darmstadt who died in childbirth in 1773 then in 1776 he married Princess Dorothea of Wuertemberg.
Zsar Paul died 1801....
Good luck,
Rena in England.