Nextcloud local clients + Cloudflare DNS Proxied = Limited Transfers to WAN speed

Not asking something, just reporting my today’s headscratching.
A week ago I enabled proxy on all my cloudflare’s DNS records. Everything worked without problems, So I didn’t pay too much attention.
Today I tried to sync some large files from my desktop to NC server using the client, and the speeds was 20Mbps max (my ISP’s max upload speed). I was sure I had more speed before, so I started looking around.
The moment I disabled proxy on Cloudflare, my speeds was back in Gigabit’s tier. (duh)