Nether chunk crashing server [1.16.5]

[VertDiNoir]

I've created a Nether portal in my base, a staircase of cobblestone fell into it before I enter and It crashed the server, I thought was something else, However when I enter again and go across the portal, an infernal rat enter the portal and crashes the server everytime i try to enter (4 times in the last 2 days), I've got the unstuck from the store, the location of my base is 9861 Y -4380, the chunk thats bugged should be the equivalent in the Nether, I put some cobblestone around the portal since I don't know if it will crash the server again if I try to break the portal.

P.S.: I've no error message to post here, I just got dumped from the server and it goes unreacheable