What are some safe overnight bonds / ETFs that I can exit any day easily?

I have some liquid funds lying in my bank. My banks give me very little interest. I don't need this money right away (I can wait up to 1-5 days, but not any longer). What type of bonds / ETF / anything else should I invest this money to get slightly better returns than banks while ensuring the safety of money?

I read about USFR/TFLO and BIL/SGOV but I am confused about which one is the best option. Maybe the best option is not one of these?

Update: I am not US-resident and don't have SSN either.