FYI, Kubuntu will still have the same core as Ubuntu, the only difference is the Desktop Environment (aka graphical interface) and the default apps installed with the different Desktop Environment. I would not expect any difference. You just want to use the most recent version of whatever particular distribution you are using.
If you want to learn Linux, then installing Linux in a VM is definitely the simplest option. If you want experience working with Linux on bare metal, then use a mid or high end non-Apple PC. Dell and Lenovo tend to have decent Linux support since both companies do sell some models with Linux as a preinstalled option from the factory (you must be careful with Lenovo since they have been caught several times with malware preinstalled within Windows or even within the system firmware...besides only a couple models are any good). While Ubuntu or Linux Mint should install & work with little hassle on most 2007 to 2015 Macs, you may still encounter some driver issues here or there.
Cameras, WiFi, and Trackpads will cause the most trouble. Plus it is best to avoid any new cutting edge hardware for a couple of years until the Linux kernel developers are able to get drivers developed and even longer if they must reverse engineer a driver because the manufacturer does not provide any hardware technical documentation so an independent driver can be developed. It is best to do your research prior to purchasing any hardware for which you want to use with Linux.
Keep in mind most hardware & popular software will only be supported on Windows as it is a Windows world...everyone & everything else are second or third class citizens. However, once a Linux system is set up, it will probably run without issue for years if you minimize installing software & drivers from outside the official software repositories....use containers for software not provided in the repositories if necessary to keep the core OS stable. If successful you get the most configurable system out there which is completely under your control.
It is best to start by learning the Linux basics by performing the simplest installs possible. Once you understand simple Linux installations, then proceed to more complicated scenarios, otherwise you may become overwhelmed by it all.
Good luck.