What is your machine‘s OS and configuration? Especially, how much memory do you have?
Look at the memory when Lr freezes. Did the memory consumption grow exceptionally?
I'm on win10, I7-7500U with 16Go ram and SSD. and when shes freez i have some 2-3 go used
but this issues start with the new version, before never freeze.
Let’s go for the standard culprit: please switch “use graphics processor off” (Edit->Properties). The graphics processor is rarely useful. Only when you have very high resolution screens (5k or higher), you will get penalized with this.