I'm not a WhatsApp user, but the circumstantial evidence of every single non technical friend I have happily using WhatsApp every day strongly suggests its not a complete UX shitfight.
I like Telegram more than either Signal and Whatsapp (security and privacy issues side)
Whatsapp sucks for me because of an unusable desktop client. Their backups system is extremely slow. I've found that messages get sent and received slowest on whatsapp when comparing with other messaging apps even if the gap is almost inconsequential. There's a woeful lack of features that I love on telegram that make the app very barebones and dull. You cannot edit messages. The replying UX is a bit irritating. There's tons of stuff but this is a small gist
WhatsApp's desktop version is crippled because it requires connectivity to your phone in order to use it. I believe they're working on a client that doesn't require that, but it's not here yet.
I have been trying the beta and it's pretty decent. Still alternate between signal, telegram and whatsapp for different groups/people, but the beta definitely seems better that what was before.
What do you find "awful" about it's usability?