3.5 month old wake windows

My baby is almost 16 weeks. Shes almost exclusively a contact napper during the day in her bedroom. At night we put her down in her Snoo in our room. This typically involves rocking and holding her, waiting a while then attempting the transfer. It usually takes a few tries before she stays asleep after the transfer. And then it’s 50/50 whether she sleeps for 4-5 hour stretch or wake up after an hour or two.

For her day naps she falls asleep SO fast. We follow the Huckleberry wake windows for 5 naps. When it’s time she goes in her swaddle, curtains closed, white noise on, and the second her paci hits her lips she’s basically out.

Bedtime for some reason is not quite as smooth. We used to do bath as part of her wind down routine but it seemed like it was too stimulating so we do it earlier now. She’s usually whining by the time Huckleberry is saying it’s bedtime so I assumed she was going to bed tired but is it possible this is happening because she’s still under tired?

We try to keep day naps to about 4 hours and the last wake window 1.45 hours. She’s awake about 9 hours during the day

Would love any advice for bedtime. And before anyone asks, she sadly does not like the Snoo to rock her to sleep and never has. When she was smaller we could crank it up and eventually she would just kind of pass out but it’s been a while since that’s worked and it just kinda agitates her now but I think it might sometimes help her stay asleep longer in the night.