No power in Europe or the world could finance all of them, simply because Leonardo produced ideas the way people produce CO2.
Thing is, that's probably a good thing because most of them would have failed, some potentially lethally. This is where people nmisread Leonardo, really. He wasn't a lone genius inventing an untrodden tech path surrounded by unappreciative morons. He lived in the middle of a highly innovative cuilture, a lot of his designs are probably not his inventions originally but stuff that was floating around, and a lot of the ideas that they sparked were off-the-wall projections with no technical expertise to back them up. In many ways, his notebooks are like finding the working notes of some highly placed, very smart Silicon Valley developer. He'll have outlines for ideas and concepts that came true (and those that didn't) in the hundreds, but that doesn't mean he's the guy who incvented cloud computing and filesharing.
Getting back to the issue, I think he would have had a better chance of more generous funding in a bigger and more powerful state. He went to France later in life, frex. If he really passionately cared to trealise his technological dreams, the Ottomans would have been an option. But either way I don't think the results would have been world-changing. Some concepts might have entered technology earlier (like the idea of streamlining - OTL it shows up in the 1570s IIRC). But he is not going to build an aerial battlefleet or steam-driven tanks, at least not without first changing the laws of physics.