Yes you can use UKUU to install a much newer Kernel like 5.0.8, I'm using LM 19.1 Cinnamon with the 5.0.8 Kernel installed using UKUU and it works perfectly fine, the only thing you need to make sure of is any Kernel module like Nvidia drivers or VMware work with the newer Kernels, if you dont then they wont work correctly and could cause system or DE to become unstable or crash, an example being Cinnamon DE will crash if Nvidia driver doesn't work correctly with Kernel, way around this is to install a version of Nvidia driver that will work with the Kernel you want to to install, just do a check before hand and fix Kernel modules before using a newer or RC Kernel and all will be okay. Best approach is to use Timeshift to take a snapshot before trying a new Kernel, if things become unstable or worse you can restore snapshot even from a liveUSB and revert changes, also if Cinnamon crashes and it asks you if you want to restart Cinnamon don't, leave Cinnamon in fall back state, then use Timeshift to restore snapshot or restart computer to a liveUSB to restore from that, restarting Cinnamon will just end up crashing again each time you try to restart it, so is waste of time. The traditional approach to enter Grub and choose previous Kernel should also work if you don't want to use Timeshit, once logged into desktop use UKUU to remove the new Kernel that caused the problem, then all should be okay again
