under proofed? over proofed? Handling issues? Something else??

I’m feeling a bit embarrassed here, but I cannot say if this bread is under-proofed or over-proofed...Can somebody help me figure out what went wrong?

Here’s what I did, based on Trevor’s Champlain sourdough bread recipe:

http://www.breadwerx.com/champlain-sourdough-recipe-video/

3-hour autolyse (instead of overnight)

Bulk for 6 hours at 26-28°C until 80% rise (not intentionally) with 4 coil fold sessions

At the end of the bulk, the dough was really bubbly and stuck to the top of the container, so I struggled a bit to get it out of it (dough handling issues at this point I suppose...)

Then shaping (very poor due to the lack of strength of the dough / To be honest I just folded the dough over itself, that’s it...)

30mn rest at room t°

Fridge overnight (12h at 3°C), wrapped in a couche: The dough stuck to the couche and came out the following morning with dried areas on the top)

I cannot say precisely how proofed the dough was at the end of the retard as I forgot to place a lid on the aliquot jar so the top of the dough sample became really dry and kind of stuck to the sides, preventing the sample to fully expand....My guess is that it was nearly 100%

Struggle to place the dough into the Dutch oven

Cooked 25mn at 230° with lid + 10mn without lid

So I believe that the bulk was too long, but I’m not sure...Or is it the handling that was too clumsy? ... all of the above??

Anything else that I'm missing??

Thank you for giving me your insight,

Gaelle