Yeah it's more popular than Arsenal Football Club ... but that's one club. There are twenty in the English Premier League. And that's a single (albeit huge) league within the English league system, which is one of about four countries in Europe alone who you could probably say the same about.
Is it more popular than Arsenal though? I think the problem here is that following a league versus following a team are different actions. I am well aware of the Dallas Cowboys and watch quite a few of their games, but I would never follow their official social media accounts, because I fucking hate them. I suppose it depends how we define popularity, but the original question was about being well-known.
Yeah this is just a discussion based on the assumption that instagram accurately reflects popularity/renown, it's entirely possible that is not actually true
But it's almost certainly not more popular than soccer.