Hey mrleafar,
Thanks for posting in Apple Support Communities! I see that your iPhone keeps freezing and apps are crashing after using an emoji keyboard. I want to provide you with some helpful solutions for this issue.
First, here's a helpful resource you can use If your iPhone, iPad, or iPod touch won't turn on or is frozen.
Are you using a third party emoji app or the built in emoji keyboard? If it's a third party emoji app, I suggest that you check for any updates for the emoji app through the App Store. If the issue persists or there are no updates available for the emoji keyboard, then try deleting the emoji app and then reinstall it.
You mentioned that you installed the latest version of iOS. Recently, Apple released another update iOS 13.4.1 and I want to make sure that you installed this update as well. For more information about the updates we have available, check out this article here: About iOS 13 Updates
Let me know how it goes. Cheers!