flip flop it or 4051 it?

1st one:
rDS(ON)= 0.540 ?

2nd one:
rDS(ON)= 1.5 ?

1st one would be better.
However,
Drain to Source On Resistance (Note 2) Rds (ON), VGS= 10V, ID= 3.4A Need a Logc Level part that switche full on at <5V.

I'd recommend something like this

Lower Rds, Logic Level Gate voltage.