Investing my first ROTH IRA funds

Hi, I (M26) have been reading about how powerful maxing your ROTH IRA is to building wealth. After finally paying off all my debt. This year i made it my goal to create a ROTH account and contribute the max amount. I maxed my contribution for the year early on but have not invested any of it so far. The balance currently stands close to ~7K due to Fidelity’s sign up bonus and interest from MM being added every month. My question is, what should i invest this account to make the most money without taking on crazy amounts of risk?

So far am thinking of splitting this fund into the Fidelity version of the S&P 500 and berkshire hathaway stock b. is that the best use for this fund? I am also wondering after seeing how much every stock has risen in Nov – should i wait until next year for a dip and invest? My initial goal was to invest the funds before the EOY but at this point, it seems like i have already waited for so long that, waiting a couple of months doesn’t seem terrible Any advice I can get would be helpful

Other than my ROTH, this is how the rest of my finances look

Yearly salary: 90K
Fidelity investment: 7K (also not invested yet) Fundrise: 1K
401K: 12K, contributing about 6%
Savings: 15K

I am also having the same confusion with my Investment account but being a little bit more patient with that for now