GPU Support in After Effects is NOT HAPPENING

As Mylenium said, and as you know after being a user for 20 years, AE is more complex than "flip the GPU switch to find optimization and performance gains." There are many GPU-accelerated effects already with more being re-written for the GPU each year, but that only matters so much when the majority of the software runs CPU-based tasks. Passing frames from the CPU to the GPU and back to the CPU can be a slow process, so even the order of your effects stack can make a difference, but nothing that would make your GPU utilization jump to a sizeable percentage.

If you're not familiar with current development situation, the AE team is in the middle of a multi-year rewrite of AE's architecture to enable true multi-frame rendering. This has been available to test in the public beta for a couple months now (you can read more here and here and performance improvements are coming frequently. In fact, recently, some major features that were added were Speculative Preview, and just last week another nice feature was added to increase performance by dynamically adjusting the amount of frames that can be rendered at once, as opposed to a fixed number all the time.

This is where the focus of AE's development efforts are right now, as they should be, and I can only imagine the future of AE's rendering is a hybrid of CPU and GPU, but the GPU alone can't completely support AE, so the main infrastructure needs to catch up and be modernized. I've already seen 3x - 4x rendering improvements in some projects using multi-frame rendering, so I recommend you take a look at the public beta. You can install it and other public betas from the left side ("Beta Apps" category) of the Creative Cloud Desktop app. These can be installed alongside the public versions without causing any issues since they get their own sets of preferences. For the most part you can even go back and forth with your project from public release to beta, so if you want, you can work on your project in AE 2021 and then render in AE Beta (this is not currently the case for Premiere, though).

Nothing wrong. You simply have wrong expectations and, without meaning to be snarky, should have informed yourself beforehand how limited AE's GPU acceleration is and where and when it is specifically used. If you really bought the card just for AE, then you have wasted a lot of money for nothing, even more so, since pretty much all professional commercial programs usually are 6 to 12 months behind in even properly supporting new cards. Outside that the usual things apply: AE is a complex program that allows different workflows by combining features differently, so performance optimization hinges on way more than buying a beefy GPU. A suitablke CPU, enough RAM, good harddrives and so on also matter and it all needs to be balanced to a certain extent. Slow disks can hinder footage I/O on the fastest processors and just in the opposite direction, fast GPUs and multi-core CPUs don't mean much when you consider that most workflows in AE are not parallelized and barely multithreaded. There's literally thousands of posts on these things here on this forum. A more specific description of your setup and what you expect might help to advise, but overall you just need to get used to these limitations. 99% of stuff in AE is far from realtime and many workflows are just clunky.

Mylenium