Extreme lagging and constant crashing

After the last 1.11.x update, the lag issue got really bad: the lag for opening chests (and chest-related items) went from 1 or 2 seconds to 10-50 seconds about every 2-3 times trying to open the item; it also started lagging for no discernable reason around every 1-5 minutes lasting 10-50 seconds or it just crashes the game to Xbox home screen; when my daughter would join as a second player on the same console, it would always crash to Xbox home screen within a few minutes. I uninstalled Minecraft completely and then reinstalled with no resulting change. My daughter stopped playing Minecraft until 1.12.0 came out.

After updating today to 1.12.0, it crashed within 5 minutes. We have now stopped playing Minecraft together.

My daughter and I have played Minecraft together a lot since we bought it maybe 5 years ago and it has allowed us to bond and brought us joy. I implore you, as a good father of a great woman, please fix this. Thank you.