There is such a thing as overdesign, but when you’re building a modern application, you must trust your designer’s sense of aesthetics and knowledge of UX patterns—two things engineers are often notoriously bad at.
No it isn't. It isn't a word process for gods sake. It has one literally one job and 300 MB is like an order of magnitude off for that. This mentalty is the slippery slope that led us to the situation in the OP today.
Not sure what you think "having an SVG renderer in memory" means exactly, typically the way an SVG renderer works is that you give it a huge chunk of memory and ask it to draw pixel data there from the SVG file. So even though the SVG is small on disk, rendering a 1000x1000 image from an SVG is gonna need a 1000x1000x3 byte pixel buffer (assuming no transparency or HDR shenanigans)
Cool, that's 3 MB