There was chemistry between Amell and Katie Cassidy, they just wrote it horribly with each of them taking turns being terrible to each other. With better writers, they could have done a proper Arrow/BC pairing and the actors would have been good in it.
I saw way less chemistry between Amell and EBR. I still don't see how this ship got started when all it had going was an occasional sexual double entendre from Felicity, that Oliver ignored played for comic relief and then the plot point at the end of Season 2 when they made Felicity out to be the love of his life to fool Slade Wilson so he wouldn't go after Laurel.
That's some serious revisionist history right there.
The whole issue with Oliver/Laurel was that it felt obligatory and mechanical, like the only reason it was even a thing was because Green Arrow and Black Canary are the comic pairing. During the time they were pushing it, Oliver and Felicity did feel like a more natural direction they were avoiding (not unlike the woes of Smallville with Clark ignoring numerous more suited female characters in favour of a flat, endless pursuit of Lana for...some reason).
I would not say the reason that on-screen relationship did not work was because they lacked chemistry, if anything that's the sole reason they ended up diverting from their plans, the idea of an Oliver/Felicity relationship wound up much more plausible and thus popular, so they went with that. The reason it didn't work was because they made it far too central to the show, and far too based in irritating melodrama that derailed Felicity's character from what it had been previous.
So yes, don't confuse them fucking up the execution with the idea that they shouldn't have ever tried it in the first place. There was certainly basis for them to try it.