I have used a Roku Express, Roku Premiere+ and now have 2 4k TCL Roku TVs. I have never had an app crash and use Netflix, Disney+ and HBO Max regularly.
On my 4K TCL TV, I've had quite a few issues with the Roku Netflix and Hulu appa... occasionally in Netflix it will just show garbled data whenever you try and play something, or on Hulu it will just refuse to actually start a show (I've noticed this happens mostly with only very specific series...) Solution is usually to restart the TV. Never had any issues while it's actually in the middle of playing anything though.
My second Roku from many years ago (first angry birds one) will crash occasionally using Netflix, will crash hard and reboot itself. Probably a thermal issue. Pretty anemic performance too. I think the software now just stresses the old hardware to the max. But to their credit, it was still receiving updates and worked. Finally retired it and replaced with new version and haven’t had it crash yet.
