tautech thank you!!! I was going crazy lol. A pico scope is literally always in roll mode so I didn't realize that I needed to manually set the siglent to that to see longer waveforms.
'It' can see the waveforms in either Roll mode, they just work differently.
In Auto mode a full screen width of data relative to the timebase setting is acquired before anything is sent from the buffer to the display. A little math on timebase setting * 14 div will give you the time before the full capture is displayed and then the display is continually updated at that 'time'/div rate.
Each has their advantages depending on what you need to do. The only thing to spirit away into gray matter is Roll mode starts at 50ms/div and slower timebase settings.