Why structure matters more on a phone
A Telegram storefront is used on a phone, often with one hand, often in a spare minute. Nobody scrolls through sixty products to find the one they came for. Categories and search are how a buyer gets from opening the shop to the right product in a few taps.
How many categories to use
Five to eight is enough for most small shops. Fewer than three and the categories do not help; more than ten and the list itself becomes something to scroll. If you need more, it usually means two categories should be merged or one product type deserves its own shop section.
Name categories the way buyers talk
Use words a customer would say out loud: dresses, shoes, bags, not apparel or accessories line. For a food shop: bread, cakes, coffee beans. If you are not sure, read the messages people send you. The words they use to ask for things are the names your categories should have.
When search is worth adding
Search earns its place once a catalogue is larger than about two screens, or when people come looking for something specific: a model number, a size, a book title. The search block matches product names, so put the words people would type into the name, including the common spelling. With its ranked search option switched on, it also looks through descriptions and puts name matches first.
Putting a product in the right place
Give each product one main category. A product that appears everywhere makes every category feel longer. If something really belongs in two places, such as a gift set that is also a candle, put it in the one where most buyers would look first and mention the other in its description.
Check it like a customer
Open your shop on your own phone and try to find three products as if you had never seen the catalogue. If any of them takes more than a few taps, rename the category or move the product. Then look at what people still ask you for in chat. Those questions point at the gaps.