Nope, wrong. That's a common misconception about CVX though. The original concept of Resident Evil 3, according to scenario writer Yasuhisa Kawamura, was "loosely set on a luxury cruise liner and had a general plot where HUNK was attempting to bring back a sample of the G-Virus". That game was initially supposed to be the third installment, but was cancelled. You can read it
here.
CVX is referred to as the "official sequel to RE2" by its creators, which is why many fans have wrongly assumed it to be the "true RE3" when it fact it was never supposed to be RE3 in the first place. It was always supposed to be a spin-off exclusive for the Dreamcast. The problem is that Capcom was developing a s**t load of multiple RE games at the same time in the late 90s which is why there is so much confusion among the fanbase regarding these games.
Remember, just because something is referred to as a "direct sequel" to something doesn't mean anything. For example, Silent Hill 3 is technically the "direct sequel" to SH1, but you don't call it "the true SH2" just because of that. When it comes to CVX, the debate is made-up by disgruntled fans whom are just salty at RE3: Nemesis being upgraded to main series while CVX got sidelined.