I made a / kill @e in nether, I respawn in the over world (I had not defined a spawnspoint in nether) and I realized that I could not take my portal ... So I tryed to create another portal but ... I could no longer place blocks. And on top of that, the chunks won't get generated anymore. Like an idiot, I obviously jumped in these chunks not generated ... I get stuck in the air ... So I tp myself at position 0 70 0 and ... I was in the nether ... I destroyed some blocks that i can reach (I still could not move) and then I placed some ... So first : I placed blocks that I no longer had in my inventory bar and every time I place a block, the adjacent blocks are transformed into blocks of the over world ... If you do not understand correctly I made a video that I posted on my channel: https: //youtu.be/0PHm8Ay0O68

Thank you for your attention.