Regular crashes, terrain glitches and resetting of gamerules to default

For a few weeks now, my game has been crashing intermittently. (Realms PS)

Crashes happen on a regular basis, and happen when I am loading in chunks. This sometimes occurs even when I am not moving. Earlier, I went onto the pause menu and the game crashed. When I logged back on, it reset the gamerules to default, meaning that mobs started to spawn in on their own, despite having previously set this to false. I even tested it in the command, and it returned as "true".

When I fly around, there are often terrain glitches, where new generations occur in previously generated chunks. These disappear, and my normal terrain loads in after a while. If it helps, there are behaviour packs and resource packs installed.

To Replicate:

World is an old world (2019), and is constantly being worked on.

Fly around and attempt to play the game as normal.