One channel or several
Splitting looks tidy and costs you reach. Every extra channel divides the audience and doubles the posting work, and small communities usually die of being spread thin rather than of being mixed.
The honest test is your announcements. If a post is useful to everybody once translated, one channel with both versions in the message works. If the content itself differs by market, split.
What the bot can do per member
The multi-language module lets automated replies follow the member rather than the channel, so a welcome or a command answer arrives in their language while the channel stays as it is. That covers most of the friction without splitting anything.
Keep one shop behind them
Whatever you do with channels, keep a single storefront. Two shops means two catalogues, two stock counts and two places to get a price wrong. The storefront chrome can follow the buyer's Telegram language while your product copy stays in the language you actually sell in.
Write announcements shorter than feels right
A bilingual post is twice the length before it says anything. Short posts survive that. Long ones become something people scroll past in both languages.
What to check after a month
Look at where questions come from and in which language. If a market is asking a lot and buying little, the gap is usually a page that was never translated rather than a channel that was never created.