When I close the opera/computer all my tabs are gone which is not supposed to happen because the setting that opens the tabs from previous use is on. Is there something I can do to fix it?

I cannot connect my flow from my computer to my phone because unlike the instruction given by opera, my flow on my computer doesn't generate a QR code as it doesn't have settings options and I cannot even use it as a single source. Idk what is the source of this problem but my flow option became pretty much useless :((((((