Help with Audio and Codecs, Resolve Studio/Linux ???

Hello. This is my first post. I'm coming from years of using Adobe Premiere on Apple computers. My goal is to migrate away from Adobe to another system and DaVinci Resolve looks like the best choice so far.
Earlier this year I built a custom PC with an Intel i9, 64GB RAM, GeForce RTX 2070, and Samsung SSD. The system is running Manjaro Linux.
I am running DAVINCI RESOLVE STUDIO 16 VERSION 16.1.2.026
PROS:
1. I love the editing interface so far. I find the tools are faster and easier to use.
2. I had no trouble importing 4K footage from a Mavic 2 Pro drone, and applying lens correction
3. The color correction/color grading tools seem far superior to Premiere
CONS:
1. Where are the audio codecs? I edited a 6 minute clip of drone footage, added some music, and everything plays fine on the timeline. I exported it and the video is great but there is no sound. I checked all of my settings and they are correct, but in Deliver > Render Settings > Audio, there are NO codecs listed in the Codec drop-down menu. Where are they?
2. I could not import any .mp3 sound files. YouTube's entire sound library is in mp3 format. I have a pretty large library of stock music and sound effects we've purchased over the years. It is 90% mp3 format. For the previously mentioned clip, I simply used Audacity to convert the track to .wav and then it imported fine. While this in itself isn't a deal breaker, the next related item might be.
3. We have YEARS of footage from various DSLR cameras, various models of GoPro cameras and other 'action" cameras, and at least a dozen different drones with their own built-in cameras. I just tried importing some footage from a GoPro HERO4 and the video looks great but there is no audio. Now I realize this might be related to the missing codecs described in item no. 1 and I'm hoping this can be easily resolved.
4. An hour and a half seems like a long time to render a 6 minute clip of 2K footage, considering the specs of my computer. But I think we can examine that after I get the above issues resolved.
I've already done several hours of searching Google, reading posts from this forum as well as watching YouTube videos. I've seen a LOT of the same thing over and over- you need to convert your files to format xyz. But many of the posts I've found are from years ago and don't address my problems directly, or don't apply to Linux.
Thanks
Earlier this year I built a custom PC with an Intel i9, 64GB RAM, GeForce RTX 2070, and Samsung SSD. The system is running Manjaro Linux.
I am running DAVINCI RESOLVE STUDIO 16 VERSION 16.1.2.026
PROS:
1. I love the editing interface so far. I find the tools are faster and easier to use.
2. I had no trouble importing 4K footage from a Mavic 2 Pro drone, and applying lens correction
3. The color correction/color grading tools seem far superior to Premiere
CONS:
1. Where are the audio codecs? I edited a 6 minute clip of drone footage, added some music, and everything plays fine on the timeline. I exported it and the video is great but there is no sound. I checked all of my settings and they are correct, but in Deliver > Render Settings > Audio, there are NO codecs listed in the Codec drop-down menu. Where are they?
2. I could not import any .mp3 sound files. YouTube's entire sound library is in mp3 format. I have a pretty large library of stock music and sound effects we've purchased over the years. It is 90% mp3 format. For the previously mentioned clip, I simply used Audacity to convert the track to .wav and then it imported fine. While this in itself isn't a deal breaker, the next related item might be.
3. We have YEARS of footage from various DSLR cameras, various models of GoPro cameras and other 'action" cameras, and at least a dozen different drones with their own built-in cameras. I just tried importing some footage from a GoPro HERO4 and the video looks great but there is no audio. Now I realize this might be related to the missing codecs described in item no. 1 and I'm hoping this can be easily resolved.
4. An hour and a half seems like a long time to render a 6 minute clip of 2K footage, considering the specs of my computer. But I think we can examine that after I get the above issues resolved.
I've already done several hours of searching Google, reading posts from this forum as well as watching YouTube videos. I've seen a LOT of the same thing over and over- you need to convert your files to format xyz. But many of the posts I've found are from years ago and don't address my problems directly, or don't apply to Linux.
Thanks