24M – Fidelity users: Should I stick with FXAIX or switch to VTI/VXUS/VT for my Roth IRA?

I’m 24M and using Fidelity for my Roth IRA. Right now I’m mainly in FXAIX (S&P 500 mutual fund), but I never see anyone on here posting their portfolios with FXAIX. Everyone always seems to use VTI, VOO, VXUS, or VT. So I’m trying to figure out what makes the most sense long-term: What should I be doing in my Roth: 1. Stay with FXAIX (Fidelity mutual fund) 2. Switch to ETFs like VTI + VXUS 3. Just buy VT and be done 4. Pair FXAIX with another Fidelity mutual fund (FSGGX/FSPSX or something else) to mimic VXUS I’m planning to go 90/10, and I only care about low cost + simple long-term growth. I just don’t see a lot of people posting FXAIX portfolios, so I’m wondering if I should switch to the ETF route or stay where I am. What do other Fidelity users recommend?