First 70.3 — is it okay to wear a swim brief under a trisuit?

I’m training for my first 70.3 (Happy Valley, Pennsylvania) and I recently bought a trisuit. One thing I’m struggling to get comfortable with is the idea of wearing it without anything underneath.

https://www.decathlon.ca/en/p/8955618/men-s-long-distance-triathlon-trisuit-rcr-x-green

From what I’ve read, most people say to wear the trisuit directly on the skin, but that still feels a bit strange to me. I was thinking of wearing something very minimal underneath, like a tight swim brief or square-leg swimsuit.

For example something like the Speedo square-leg swim brief style (not regular underwear).

My thinking was:

• it’s designed for swimming
• quick drying
• tight enough not to bunch under the trisuit

Has anyone done this for a 70.3?

Any downsides I should know about (chafing, water retention, etc.)?

Also curious whether people started this way and eventually stopped wearing anything underneath.

Would love to hear what experienced racers recommend.

Thanks!