I’m also a noob, and I understand my experience may be an outlier, but I’ve had better luck running programs from official repos and AUR better on mainline than with the LTS kernel when I was running Endeavour on VM and when I was still using Manjaro and Arch. I also have less issues when switching between desktop environments (between KDE, Gnome, LXQT) on the mainline kernel. (I use a thinkpad x270 with i5-7200U, 16g ddr4 ram @ 2133)
It is wise to follow the advice of the more experienced members of the community though and have a backup kernel
Ok, say, I had been running the mainline kernel, and switch to the LTS kernel which might be of a lower version than mainline. Will this conflict with programs and drivers?
Not in most cases. User space applications should always work with either kernel.
There are some out of kernel drivers that are specifically tied to a kernel version such as nvidia but these aren’t as common. Also, there is a matching nvidia-lts in the repos.
I switch back and forth between kernels pretty regularly. Depending on your hardware, mainline kernels will often have issues during the early point releases.