It involves several steps, where you more or less first install a firmware version that allows for Beta, then install the Beta. Data shouldn't be wiped by this, but there are no guarantees. You also need to download the firmware files from the internet and use a flashing tool like Odin.
So yes, it is possible, but I personally can't recommend it as first of all it's a beta - it can have bugs that makes your phone not behaving as expected. Second - there is always a risk of bricking your device when flashing if the usb cable isn't attached securely or something else happens. And lastly, you won't get this as a OTA upgrade, instead you have to rely on third party resources for downloading your files, which always is a security issue...
If you still want to do it; just google "install One Ui 6.0 beta in unsupported regions" and you'll surely find what you need.
