How to use Bublr with Safari v14 (desktop) in 2 steps
First, why? Only Safari v15+ natively allows WebGL2, but on Safari v14, you need to enable it manually. Once and for good.
To check your version of Safari: Safari menu > About Safari
Step 1 : reveal the "Develop" menu


Step 2 : activate webgl 2.0


Now, reload bublr.
Note: on Safari 13, the same menu is also available but it is not enough to run Bublr.