In reply to lobsterghost1, please see below response from WhatsApp support wherein they state my issue is most probably an iOS one with the iPhone Emoji keyboard (I can't find how to attach a PDF file to this post, hence the text from WhatsApp).
I have carried out the following additional troubleshooting steps: (a) checked that the emoji keyboard is enabled (b) ensured that both my phone and WhatsApp are running the latest versions (c) reset keyboard dictionary on my phone and (d) deleted and downloaded new WhatsApp app.
WhatsApp Response
I understand your frustration. I'd be happy to help you with the issue you're experiencing with WhatsApp emojis on your iPhone SE 2nd Generation running iOS 18.6. Since you've already tried restarting your phone and toggling the Stickers option, I'd like to suggest a few more steps to troubleshoot the issue.
Firstly, please note that emojis are not built into WhatsApp for iPhone, but rather are part of the iPhone's emoji keyboard. To access the emoji keyboard, you can tap the "Globe (globe)" icon or the "Emoji (smiley
face)" icon on the keyboard. To troubleshoot the issue, I recommend checking if the emoji keyboard is
enabled on your iPhone. You can do this by going to iPhone Settings >General > Keyboard. Make sure that the emoji keyboard is enabled and that you have the latest iOS version, as Apple regularly introduces new
emojis in new iOS versions. Additionally, you can try resetting your keyboard dictionary in iPhone Settings > General > Transfer or Reset iPhone > Reset > Reset Keyboard Dictionary > Enter your passcode, if prompted > Reset dictionary. This may help resolve any issues with the emoji keyboard.
If none of these steps resolve the issue, I recommend contacting Apple Support for further assistance, as the issue may be related to the iPhone's emoji keyboard rather than WhatsApp.
Please let me know if you have any further questions or if there's
anything else I can help you with.