I tend to pH my stuff to 6.7-6.8 and hope that the soil buffers the ranges either side of it.
aiming for 6.5 is fine! just avoid adding too much acidic levels to achieve it - slowly over time is best! 4.5 sounds like a bit in the harsh side, so keep it pH’d above 6.0 and you should be okay.
do you water them to runoff?
she looks way better so you’re getting there bro