Playback (edited) pictures and 3D titles

Hi,
I'm trying to make a video with pictures (png) and a 3D title (spin twist) in the end. To the pictures I apply a zoom in effect.
I'm having a lot of stuttering in the playback of the video (the background music stays mostly fine).
I tried to generate optimzed media, render cache, playback proxy at quarter resolution but the problem stays.
Strangely enough, if I move the playhead along the clip it shows smoothly, so it's only the playback that goes wrong.

Any suggestions for smooth playback?

Thanks a lot in advance.

P.s. I'm running on a Mackbook pro mid 2012, High Sierra and DaVinci Resolve 15 (free version)

A MacBook 20121 is quite underpowered for DR. What is your timeline resolution?

Hi Uli,
I noticed indeed that my MacBook pro has a hard time. My timeline resolution is 1280 x 720 HD 720p.
Which settings, or laptops (Mac) would you recommend? I just wanted to make a simple video.

Thanks,
Efraïm