Investing of sum of money

Hi, have some money that I like to invest.
Normally, I would do lump sum investment given the research that shows lump sum to give better returns.

However, given this time where there are strong feeling that there might be a recession looming what with 2 ongoing wars, and moody warning of massive US debt, lump sum investment is giving me cause for concerns.

Would like some advice on how best to invest. Some thought:

1. Continue to Invest in SP500. Rather than lump sum investment, do regular monthly investment instead to smooth out the peak (and dips).

2. Invest in Fixed Deposit. I'm in a country where FD rates is around 3.5%.

3. IBKR portal offer an attractive interest rate of 4.8% source. I can put money there and then do DCA [see 1 above].

4. Treasury bills. More complicated to buy in my country.

Welcome other ideas. Thanks.