Lottie animation: gotoFrame and showLayer

I can play my lottie on my esp32s3 on lvgl 9.2.0 just fine. However I want to go to a specific frame and pause there. The lottie file also has different layers/objects on top of each other that I’d like to show/hide. For example a battery loading animation needs to show a specific frame and hide the layer that shows a “flash” to indicate charging.
The controls of the animation seem to be very limited:

a = lv_lottie_get_anim(lottie);
lv_anim_set_duration(a, 5000);
lv_anim_set_repeat_count(a, 0);

works but adding it to a timeline and controling the timeline controls doesn’t:

lv_anim_timeline_add(anim_timeline, 0, a);
lv_anim_timeline_set_progress(anim_timeline, 20);
lv_anim_timeline_pause(anim_timeline);

So how to show a specific frame and are layers show/hide supported? Must I revert back to rlottie? If so, is there an example?

Many thanks.