That's the annoying thing with WhatsApp, Slack, Discord, etc. Let's say I've got a personal client (that I'm definitely not using...) which works so much better than the official one. I cannot distribute it or use it according to their rules. It's forced enshitification, even though we have better options.
On the good side though - if you're replicating the official behaviour close enough... maybe nobody will know. But then you have to make sure everything, including key sort order, and JA4 of requests matches. And that's tough...