GBoard always starts lagging / crashing after ios update
The assumption you're making is that the problems you're having are related to the upgrade to iOS 13.
Now, while this assumption may be correct, it's also the case that around the same time iOS 13 was released, Google also updated Gboard to v 2.3.0 and, not long after, to 2.3.1. In other words, not only did the version of iOS change, but also the version of Gboard.
As a troubleshooting step it would be good to test the latest version of Gboard on an iPhone that's not running iOS 13. I do appreciate, however, that's not necessarily an option for you.
So, what I'd try is totally removing Gboard from your iPhone and then re-installing it from scratch.
Removing Gboard
- Open Settings
- Go to General > Keyboard > Keyboards
- At top right, tap Edit
- In the list tap on Remove next to Gboard
Re-installing Gboard
- Download Gboard from the App Store
- Configure Gboard as per your preferences (keyboard, full access, etc)
Now test to see if that's helped to alleviate the situation.
Yes I had a similar issue: periodically Gboard keyboard would crash after a second or two (and iOS replacing it with standard keyboard). Not doing anything, simply clicking to write, wait 2 seconds and the screen would change with the standard keyboard. The first time I solved it like I deleted the Gboard app and reinstalled it & rebooted. But now I tried something else & worked: I went to Gboard app, and into the Keyboard Settings menu it has, and for starters disabled all its settings (they are blue radio buttons, put them off all). Then, whenever I would access keyboard, Gboard keybord woud pop up and stay up. So it would function. Then putting back just the settings I need: sliding writing and automatic correction. Works like a charm. Of course don't forget to be up to date with all your iPhone iOS version and GBoard app.
Go to Gboard's Keyboard Settings and disable "Share usage statistics". That worked like a charm for me. Gboard stopped crashing every time I edit a text. I am guessing there is a problem with that setting where it crashes the keyboard.
If the other options don't work, try disabling Allow Full Access under Settings > General > Keyboard > Keyboards > Gboard.
This disables the Google Search feature, but stopped the crashes for me.