Mobs being spammed into a nether portal completely breaks the game.

After creating a mob grinder that focused on sending guardians to the nether to stack up then be killed there, I was greeted with a crash anytime I loaded the chunk that the receiving portal was in. Now that chunk is inaccessible through the portal or from another angle in the nether. I also have to play on the 6 chunk render distance to keep the game from crashing when I go through my main nether portal. I was able to test that any mobs spammed into the portal (another player on the other side will allow the mobs to enter the nether and evade the crash) will cause a crash. I was not able to discover any fixes for this, as the chunk did not seem to exist anymore. I tried to fill massive amounts of blocks with air in hopes to destroy the portal but I only got an error message saying I couldn't fill "blocks outside of the world" (I know was in the area of the portal because I could fill almost anywhere else with air). This also didn't happen from nether to overworld.