Mr. Kuzmin is CEO of Mass Network.
He is founder and co-owner of Mycelium.

That is the only strong connection.

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One can easily juxtapose the teams:

Swish: https://swish.mycelium.com/team.html
Mass: https://mass.network/team.html

Same people:
(1) Alexnder Kuzmin (CEO in one case, founder in other). Swish CEO is EUGENIO ALONGI.
(2) Sam Cheng Hung, developer.