How do you get the Season 2020 - Flex Gold Icon?
It was a ranked reward. Riot's description in the client reads: “This icon was earned by finishing Gold in Flex Queue in Season 2020”
Is the Season 2020 - Flex Gold Icon still available?
No. The Season 2020 - Flex Gold Icon was a ranked reward. To earn it, you had to reach Gold in Flex during Season 10 (2020). Riot does not hand out past ranked rewards again, so you cannot earn this icon anymore.
