I am a big guy who wants to buy a race bike
Fact: True pro-level road racing bikes from all eras, including but not limited to the current iteratons, prioritize being light as possible while durable enough, and the right kind of durable, for a pro racer.

Fact: A heavy non-racer riding for fitness and pleasure doesn't really get any utilitarian benefit from the extra bit of weight reduction that distinguishes really high-end bikes, at all, other than potentially the psychologically driven kind of utility, i.e. you have a light, sexy bike and that motivates you to ride more.

Fact: There's a whole ton of ways the durability factor could bite you. That said, none of them are individually super likely. A related thing is that really high end bikes cost more to maintain and replace components on, especially if you care about keeping everything high end. 

Fact: Wheels are going to tend to be the biggest and/or most immediate trouble spot if you do go for it.

Fact: Pro race bikes tend towards offering position choices that work for pros, and it's very common for this to create difficulties or impasses for non-pros doing long-distance recreational riding. The "endurance road" category was basicaly invented to address this.

Fact, but more contentious one: There can be some nice things about having a really stiff bike as a large, strong rider. That said, the importance of this as it relates to what modern humongous-tubed carbon frames actually give you over the competing options, like say a nice steel frame with 31.8 downtube and 28.6 seat and top tubes, is often overstated.

Opinion: Do it if it's what you need to do. Meeting your goals and having fun while making emotionally driven equipment choices is a lot better than nothing. You won't be the only one. Do make sure your fit on the bike is uncompromised, which you may find to be a criteria that other decisions have to flow from. All that said, many of us find there's another kind of emotional satisfaction in having bikes that actually make sense for who we are and the kind of riding we do.