Realm reset chunk of world to partial spawn state

We spawned into our realm. We made a guardian farm, and several other large builds on this particular chunk. In the process of us logging off and coming back later, the chunk was set back to how it was initially (like spawn) with a few blocks here and there of the work we did. If anyone can help id greatly appreciate it. It's over 120 combined hours of work we've done and it's gonna suck to lose it. It happened after the realm updated to buzzy bees update