No argument intended. I maintain a running list of movies with variable aspect ratio on another site, and I try not to update it until I find confirmation of the aspect ratio from someone who has the disc in hand. You mentioned that you preordered the 3D disc for Eternals, so you seemed like...
The 3D Blu-ray of Spider-Man: Far from Home is 2.35:1 with no variable ratio. The VAR version is only available in the "IMAX Enhanced" streaming version.