Premiere/Media Encoder 14.5 - Not utilizing GPU correctly?

I updated my Premiere and Media Encoder a couple of days ago to the latest version distributed in Creative Cloud and, since then, my previewing in Premiere and encoding via Media Encoder is MUCH SLOWER than it used to be. I've checked my settings and my encoding is set to use hardware everywhere I see a setting for it. The GPU is a RTX 3090 at the latest driver version (456.71)

Here's a comparison of two renders done, one before the update, and one after. The project settings are the same and the source video file is read from an SSD so there shouldn't be any I/O bottlenecks.

10/18/2020 08:39:59 PM : Queue Started

- Source File: D:\Streaming\Video Editing\Ghost of Tsushima\Ghost of Tsushima - 15.prproj
- Output File: E:\Stream Archives\Ghost of Tsushima\Ghost of Tsushima - 15 - Bandit Problems.mp4
- Preset Used: YouTube 1080p Full HD - 8Mbps 60fps
- Video: 1920x1080 (1.0), 60 fps, Progressive, Hardware Encoding, 02:14:54:49
- Audio: AAC, 320 kbps, 48 kHz, Stereo
- Bitrate: CBR, Target 8.00 Mbps
- Encoding Time: 00:39:18
10/18/2020 09:19:17 PM : File Successfully Encoded

10/22/2020 08:45:26 PM : Queue Started

- Source File: D:\Streaming\Video Editing\Deliver Us The Moon\Deliver Us The Moon - Part 1.prproj
- Output File: E:\Stream Archives\Deliver Us The Moon\Deliver Us The Moon - 1 - Everything's Wrong.mp4
- Preset Used: YouTube 1080p Full HD - 8Mbps 60fps
- Video: 1920x1080 (1.0), 60 fps, Progressive, Hardware Encoding, 02:02:17:22
- Audio: AAC, 320 kbps, 48 kHz, Stereo
- Bitrate: CBR, Target 8.00 Mbps
- Encoding Time: 03:59:03
10/23/2020 12:44:30 AM : File Successfully Encoded