macOS client "Suggest Stickers by Emoji" has been broken as far back as 2024, with no attention given by Telegram team. It has been reported multiple times (see links below) and this attempts to summarise the same bug.
The user's stickers are not suggested at all by the client.
If the setting is set to "All Sets," this is often reported as irrelevant stickers being suggested.
If the setting is set to "My Sets," it becomes clear what the issue is -- no stickers are suggested.
This issue exists in macOS native version (both App Store and dmg versions), and not tdesktop.