The phrase "although arguably it is" is correct and usable in written English.
It can be used to introduce a point of view that may be contested or debated, suggesting that there is a reasonable argument for the statement that follows.
Example: "The policy has been effective in reducing costs, although arguably it is not sustainable in the long term."
Alternatives: "though it can be argued that it is" or "even if one might argue it is".
And to bring some human scale into the modern workplace, although, arguably, it's more about making people happier with their miserable lot than about actually changing the political system that has created that miserable lot in the first place.
When I first explored the Kiiroo system three years ago and found it fascinating although, arguably, it was like having sex with a 3D printer.
Although I just mocked Mensch, arguably it's to her credit – not the drugs or the admitting to taking them; rather, because at least she has a past.
Gauguin's desertion of his family, although arguably it merits reproach, is also arguably justified because he succeeded in producing beautiful pictures.
Although this is arguably unfair, it is their decision, and complaining about the fairness of a ban probably won't go over well anyway.
The issue of caste discrimination is by no means limited to India, although it is arguably here that the most severe atrocities occur.
The contest for the Labour leadership has so far failed to test the candidates on this issue, although it is arguably the most vital one that the party and country face.
It's a literature whose boundaries lie only at the limits of the human imagination, although it is arguably better at predicting social change than it is at envisaging scientific developments, of which its track record is lively, but not as accurate as one might wish (it wasn't great at predicting advances in technological miniaturisation).
Divesting from problematic companies and industries is a protest tactic with a long history, although it is arguably best-known as being one third of the boycott, divestment, and sanctions campaign that played an important role in bringing an end to the apartheid government of South Africa.
What's interesting about this equation is that, at least on our first impression, we'd say the new ES is less sporty than the Benz, although in some sense it is arguably more luxurious.
