Titles Look Horrid in Final Render

I don't know why but I can't get my titles to look good. I don't know the exact terminology to describe it, but after rendering, the titles look like an overly-compressed JPEG image. The edges aren't sharp. There are terrible jaggedy artifacts. It just looks like I used a low bitrate render. But I'm not using a low-quality render. I'm using the following settings:

1920x1080

60fps

progressive

square pixels

"render at maximum depth" is ticked

"main" profile (I've tried all the others too)

VBR 2-pass

target bitrate - 16

max bitrate - 20

"use maximum render quality" is ticked

format: h.264

These settings match my sequence settings, yet the titles still look like garbage. Here is an example video (titles near the beginning - first 15 seconds or so):

Portland Trail Blazers vs Utah Jazz - Full Game Highlights - October 7, 2018 - YouTube

I've tried all the different profiles. I've tried upping the bitrate to 30 . . . titles still look . . . not sharp. I haven't tried a different format yet. Maybe that's the problem?