To flesh out things to where you could actually make a reasonable pitch with things like realistic time estimates and documents that would be useful to read then you'd have to have already done it, it'd be trivial, or you apparently have plenty of spare time to do serious spikes in your day to day. You'd also have to have the spare time to update these project ideas as the months pass, the product and codebase changes, etc.

I'm often convinced people extrapolate their insane luck with teams+companies and assume every other company/team can replicate their results. I have a hard time finding people in high level positions who give the slightest of fucks about engineering focused tasks but I am someone who works on product teams. The target goal is always about making money - not saving money or improving velocity.