I think it depends on the platform. I use Fidelity and they...

I think it depends on the platform. I use Fidelity and they charge a $50 fee for a foreign transaction. The majority of my shares of BRCHF (formerly known as AZKLF) were purchased on Fidelity, however, I purchased a large quantity at a time. I would not buy them in small parcels.

If I do want to buy small amounts now (although I won't actually hold the underlying stock), I would probably purchase the ADRs, especially for my individual (non-retirement) account, since I will have access to sell those sooner and not have to pay any fees through Fidelity. However, any ADRs I purchase will probably still be held for over a year, since that's the lowest tax rate on capital gains I can get (15%).