Any way you slice it 6 months living expenses earning no interest is a huge expense. For the average person putting that away at 30 means delaying retirement by around 2 years. Worse you need to keep adding money in to keep up with inflation.

It’s reasonable to keep 6 weeks of living expenses on hand, but the rest doesn’t need to be in cash as long as you can quickly liquidate it.

Agree, the only requirement is sufficiently liquid, feel free to earn as much as possible given that constraint

If you can't withdraw money from your mutual fund, or put a charge on your credit card, paying rent for 6months is the least of your worries.