I think just relying on updated parameters from Arcane may not prove to be related to hashrate in any way.
Then you should come with your own numbers, right?
I'm actually surprised it would be only 19%, from the companies I was tracking last year they had by the end of 2021 at least 20exa of hashrate available, and this is without counting Core as they didn't release any details, all of them have on order more than 75 exa of gear, that would bring them at nearly 100 Exa by the end of 2022, so about half of the current or taking into account, this is added hash on top of it about 40%.
Foundry has 16-19% of the hash rate and it's only for large US-based clients, so I would expect the numbers to be far bigger.
With Intel getting into building mining chips, I would not be surprised if the US miners' hash rate will keep increasing in the near future faster than in the rest of the world.
Till Intel start producing those chips and their clients start mining they have a ton of orders from Bitmain, I don't remember if it was Hive or Mara that had reserved shipping even in 2023 already, probably Intel will be the one cementing the 90%.
When corporates buy bitcoin it moves towards further centralization. Microstrategy holds an awful lot of bitcoins that can anytime bring the market to its feet if they wish. That's the actual risk I see, more than a miner going public.
Microstrategy dumping their coins will crash the price once and that's it, a single company owning 50% of the hash rate can decide to make a lot of stupid things that will hurt the chain forever. Remember what plans Mara had with their pool!