The issue is:
1) Your Savings Rate is a much bigger influence than your ROI in the early years, and
2) ROI is a much bigger influence than your Savings Rate in your later years before FIRE.
So for example the race from $10,000 to $50,000 will be almost entirely based on your savings rate, but the race from $1,000,000 to $1,500,000 will be almost entirely based on your ROI.
If you are 10 years away from FIRE, that means your projected ROI won't really kick in as a strong influence until - let's say - five years from now. So you're not projecting your retirement timeframe based on performance for the next few years with the information you have available today, you're doing the much harder task of projecting returns for 2027-2032 with the information you have available today. Hell, if you could predict the price of any random commodity in six months, you could just become a multi-millionaire that way, but to do so would be just guessing.
As if that wasn't hard enough, the sequence of returns matters too. A massive market crater in 2022-2025 would benefit you greatly by raising the likely returns in the decade afterwards. If the crash doesn't happen until 2032 though, it'll severely damage you, even if the market ends up in the same place in either scenario.
The point is to focus on that savings rate as much as possible now, because that's what matters a lot more than guesses about future returns. Increase your income, cut your expenses, move to a cheaper/closer to work area, just do what it takes. Whatever you do, don't take your first $20,000 and try to string together a series of winning stock picks or WallStreetBets gambles until you inevitably lose and set yourself back a year or three.