Experiencing Severe Slowdowns on Btrfs with RAID 5 during High Write Operations

I have a PowerEdge R720 running on RAID 5 with a total of 20TB of storage. I switched from ext4 to Btrfs for the safer anti-corruption features since ext4 kept corrupting my files when the server would shut off suddenly due to power outages.

Anyway, I'm having an issue with my server slowing down to a crawl during high writing operations. I'm usually downloading hundreds of gigabytes at a time. Some examples of how slow it gets are when installing packages, which usually takes around 2 minutes when normally it's like 5 seconds. Another example is loading sites like Sonarr and Radarr, which takes ages to load and run operations.

I didn't have any of these issues on ext4. I'm currently running a SMART test, but that's going to take about a day and a half to complete. I improved the fstab line, which helped the speed a little bit, but it's still at a crawl. Compression is also off.

/dev/disk/by-uuid/16417af9-0795-4a0e-b0cb-c29427019084 / btrfs defaults,noatime,nodiratime,space_cache=v2,autodefrag 0 1`