More blur == larger aperture, if other factors remain fixed.
From 85cm you’ll need a 35mm lens to get head & shoulders in shot, possibly a 50mm if you can drop the camera back a way.
You can get a f/1.8 for a reasonable price or a f/1.4 for a lot more. $£€100 1.8 to $£€ 500 for a 1.4.
The shorter your lens, the larger aperture you will need to blur the background.
Examples… (ignore the quality, these were lit by the computer screen & one room light & the ISO ramped up to max – not exactly ideal lighting)
Bear at 85cm, centre of flowers test print on wall another 165cm
This is on an APC-C with a 1.5 crop, the Canon is a 1.6 crop so your framing would be tighter.
Personally, I’d always go for the 50 & try to gain some distance rather than the 35 which can get a bit ‘pointy’ for me – big nose, little ears.
If you don’t want to hear the autofocus motor, don’t use the built-in mic.
Pulling focus to follow a talking head at 65cm on either a 35 or 50 is going to be pretty distracting. You will probably have to choose between razor-thin DoF & not making your audience dizzy by sacrificing some of your blur.
Another idea, if you want to “outcool the other kidz” is a fake anamorphic lens (or a real one if you can afford it, but they’re expensive 😉
This is a 52mm lens (a Helios 44M) I got from a Russian lens mod company, for $55 USD. It has a ‘fake’ iris inside which gives the impression of an anamorphic effect on bokeh. It is totally manual, so no more follow-focus issues to worry about. Look at the light I put in the scene, which is a single LED point-light. It gives it a vertical oval shaped bokeh, characteristic of anamorphic lenses. It’s actually only an f/2, but it feels much wider because of the distortion in the out of focus areas. Crop to a more movie-style 16:9 or even tighter & there’s your fake cool lens effect…