I basically use emoji like you.

Reactions: 👍 = okay. ♥️ = thank you/okay/general affinity. 💯 = I agree (mostly used in group chats). 💪, 🔥🎉,🎊, or 💥 = nice work/congratulations. 🥲, 😢, 💔, or 😭 = I got your message, but I don't like it.

Sometimes I will use them to emphasize my own messages. Like I will say "Sorry I can't make it, already have other plans 😭". But the intent here is to indicate that I am disappointed, but don't feel too bad about it. I would never say "Sorry your dog died 😭", because emoji by their nature add too much levity to such a statement.

And then, of course, there are the flirting emoji, 🍑😍😈🔥🤤😏😳😘🥰😍😜🥵🍆💦🚩, which I probably use too much for my own good.

Using multiple emoji in a row is used to indicate emphasis or excitement. So a friend's announcement of an accomplishment in a group thread might earn a 💪💪💪, or a partner's sexy pic might get a 🥵🥵🥵 (followed up with an appropriate text response, of course)

The use of multiple emoji to indicate a thought or feeling is used as a joke, basically making fun of the way boomers use emoji. My favorite example being 🎸🇺🇸🦅, which is also an Always Sunny reference.