Are you saying the surface in the picture is the one that touches the bed? If that’s the case it should be nearly perfectly flat and smooth(ish depending on bed texture). If that’s the orientation it prints in there’s still an issue of distance and possibly belt tension or something else because of those waves and deep grooves. There’s a bunch of different methods to level a bed but ultimately you want the nozzle to slightly squish the filament it is putting down, in the picture it looks like it might not be.

As for the bed being clean, if you haven’t yet I’d definitely spray some isopropyl alcohol and wipe it off, taking care not to touch the bed with your hands at all – oil from your skin will easily cause adhesion issues.

Larger prints in general, and especially if there’s temperature variance while printing (drafts), can start to pull off the bed as the material contracts. You may need to add a brim in your slicer to help keep it welded down. When it’s necessary to use one will be a learning experience as you get used to your particular printer and environment.