Excel is a monster, and much more powerful than Google sheets in many ways, but in my experience, Google docs apps are a little better for collaboration, and they integrate a little tighter with each other.
I've also never had trouble pasting a spreedsheet selection into a word document. Email is a nightmare in general though.
I'm not sold on collaboration personally. I've had to do it a bunch since the pandemic began and I've found it to be an anti pattern. One of the big inconsistencies is that cells in sheets don't update while being edited while collaborating, which is not great if you have a spreadsheet heavy workflow. Docs is impossible to replace that though, because it's auto formatting is draconian and always seems to reset its preferences. When editing docs we spend more time formatting them then creating the content.
How much of this is really related to technology? I do a lot of writing in both Word and Google Docs and see different sets of problems for both products. Having a group of people jump into either and expecting a good product (and experience getting there) is unrealistic.
With the pandemic, I think people have been trying lots of things without understanding what will be most effective. At least early on, there was a feeling that people had to be seen to be productive. It's nothing like real remote work.
For important docs, I still come back to having individuals write their content and only then does one person attempt to assemble it. The individuals often need their own independent reviews and consultation anyway before they have a decent draft. In some ways it improves visibility and helps with keeping folks on schedule too.
I use text editors so I can think about the content and if it is going to get prettied up with fonts it goes into a target system that supports markdown (confluence, git, email, etc..). If you are flummoxing around in a word processor or sending around formatted docs that aren't PDF I fully expect people to be looking at you sideways.
I hate to inform you that, yes, writers do indeed use “that garbage”. I’m married to an author who regularly uses Scrivener to write. But anytime she has to send anything to anyone she has to convert to a Word document and send that out. Everyone uses Word that she interacts with. (Though author friends of hers might also use Scrivener for their writing)
Writers who understand git, let alone Markdown, are going to be extremely rare. You’re in a bubble if you haven’t encountered how dependent the writing field is on Word documents.