Apple - How to upgrade to Big Sur?
While Big Sur has been relased as a public beta, it's not ready for general consumption. It's going to have issues and users are expected to know how to get around issues and at least research. Let's face it... you're jumping into the deep end of the pool - do you know how to swim or at least did you bring your floaties?
From the Beta FAQ
Please note that since the public beta software has not yet been commercially released by Apple, it may contain errors or inaccuracies and may not function as well as commercially released software. Be sure to back up your iPhone, iPad, or iPod touch and your Mac using Time Machine before installing beta software. Since Apple TV purchases and data are stored in the cloud, there’s no need to back up your Apple TV. Install the beta software only on non-production devices that are not business critical. We strongly recommend installing on a secondary system or device, or on a secondary partition on your Mac.
I'm not saying this to discourage you, in fact, I encourage all users to try out new things because it expands their skill set. However, I do fear for users who want to upgrade to the bleeding edge on their only computer to beta software (regardless if it's Windows, macOS, or even a *nix) without having some sort of way to escape if something goes sideways. Ask any long time user here how many questions we each have answered where having a Time Machine backup would solve pretty much all problems...
All that said... You can do an in place upgrade and a wipe and install . I prefer the wipe and install (via USB Installer preferably). After you've downloaded the installer....
sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/startosinstall --agreetolicense --forcequitapps --nointeraction
Wipe & Install:
sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/startosinstall --eraseinstall --newvolumename "Macintosh HD" --agreetolicense –forcequitapps --nointeraction
To create a USB installer:
sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/DRIVENAME --nointeraction --downloadassets
In your case, the Mac doesn’t meet the requirements for Big Sur. You did everything correct, except checking the supported hardware.
Allan has a good answer for overall relating to BigSur. Here's an answer for the specific make and model. According to Apple's website, there are a few models that supported Catalina that will not support BigSur (macOS 10.16/11).
The machines that support BigSur are:
- MacBook 2015 and later
- MacBook Air 2013 and later
- MacBook Pro Late 2013 and later
- Mac mini 2014 and later
- iMac 2014 and later
- iMac Pro 2017 and later (all models)
- Mac Pro 2013 and later
Big Sur Preview (Apple's website) Navigate to near the bottom of the page to find compatibility information.