First, render time depends on:
- Your composition settings including frame rate and frame size
- The type of source footage you are using
- The effects you have applied
- Your system resources
Second, After Effects is for creating shots you cannot create in a non linear editor. Form your brief description it sounds like you may be using AE to edit rather than create effects shots or motion graphics. If that is the case you should explore using Premire Pro or another NLE to do most of your work and limit the AE comps to just the shots that cannot be done in any other way.
Third, If your effects require GPU enhancement, like using the C4D renderer, then you should be rendering to a visually lossless format using the Render Cue and one of the presets in the Output Module. Then you would load that visually lossless copy of the project and compress it using one of the standard h.264 YouTube Presets that matches your frame rate and frame size. Unless you have expert knowledge and experience in video formats, compression and all things related to video you should not ever see the word custom in a composition setting or a render setting. 90% of the adjustments that the inexperienced make to render settings cause something to be off and the quality of the end product to go down.
Lastly, YouTube will recompress everything you send it but if your upload was created using one of the presets in the Adobe Media Encoder then the file matches YouTube standards and because the file matches the standard the end result is a video of higher quality than you will get any other way. The worst thing you can do is to send YouTube or Vimeo or any other streaming service a file that is way out of spec. Sending a visually lossless file to any streaming provider will give you an end product that is not as good as it would be if you sent a video compressed with one of the presets that matches your frame size and frame rate.
Ome more thing, there's no way for us to tell whether you need to upgrade your machine without OS, system and workflow details down to the last decimal point.
Thanks for the reply! I have considered trying Premier, but it seems that everyone in my industry uses After Effects. I sell instrumental music through Youtube, and so the video consists of another artists music video (1080p and muted) along with some effects such as an audio spectrum, text, and glow. Are these features things that would be easier done through Premier?