Figma features a highly beneficial command (Shift + 2) that enables you to efficiently zoom in on the selected object,
This feature significantly enhancing the workflow,
and it would be great to see this feature in illustrator.

Just as you can "Fit Artboard in Window" ⌘ 0,

And "Fit All in Window" ⌥⌘ 0,

It would be nice to fit (selected) Object to Window with simple keyboard shortcut.

I know Zoom ⌘ + with "zoom to selection" turned on does this somewhat. But often I have to continue to zoom up (+) in order to get the object to fill the screen.

The question then might be, well how much should the object fill the window? I think 150% is probably a good starting point, but being able to set the zoom percentage factor would be cool too.

This feature is still not available in May 2021. The completed tag is false.

See https://graphicdesign.stackexchange.com/a/99417/8980 for a workaround using Actions.

Also see this Action workaround using Fir Artboard to Selected https://graphicdesign.stackexchange.com/a/99417/8980

Tony, for now you can use this script:
https://ais.sergosokin.ru/view/zoom-and-center/

It would be great if I could hit a single hot-key to fully frame a selected object on my screen. Similar to how some 3D packages where you can hit the letter "F" and it fills the screen with whatever is selected.

At the moment Actions can't record changing the artboard size to fit the artwork. I download a lot of templates in different sizes. I can do this manually but it involves a few steps. If I can have a 1 button action I can place 10 templates on 10 artboards and use an action on each artboard (one at a time or all) it would save me so much time. At the moment it's Object>Artboards>Fit to Selected Art or Fit to Artwork Bounds.

This option is still NOT in illustrator as of May 2020, Neeraj's COMPLETED tag is utter nonsense. You want to select an object and press a key combination so that object becomes the center of the screen AND FILLS the screen. He most likely never used illustrator for creation as an artist and either didn't read your request or didn't understand it. He is referring to the stupidest zoom created ever which is ZOOM TO CENTER. I call it stupid because it is actually only zooming 50% of the current zoom level AND sliding the center of selection to the center of the screen. There is a Fit all in window which only works for multiple artboards. There used to be such feature; I believe illustrator 4 came out with it but was taken out.
Anyway, there is a way to make a script to do this and here is the link for it. http://www.wundes.com/JS4AI/
You can use it on either Mac or PC.

Fit selection would be consistent with XD. Zoom selection is there, why not build out Fit Selection?

Just like you're able to fit the artboard to selected art. Is there a way to fit/scale an object/art to another object? Just scaling the first object to the second one, rather having to do it manually through transform or scale.

Currently, I cannot record "Fit to Selected Art" in an action. Please make actionable.

There's a script that does this. Record an action that launches is and bind it to the shortcut.
The native way though will be great thing to have.

When working on details / prepping parts (e.g. outside the artboard), Fit Canvas, nor Fit All are of any use. Fit Selection would be a nice extra.