EGPU for 2017 Base MacBook Pro for Premiere Pro

My situation- I have a 2017 low end MacBook Pro with dual-core 2.3ghz with integrated Iris 640 graphics. I didn’t buy this for video editing, but current circumstances have pushed me that way. For my business I keep videos to 5-10 min 1080p so these aren’t too bad on the render time. The problem is I am doing longer 1+ hour videos for my church and I am getting render times in the 14 hour range even bringing resolution down to 720p.

My question- would an egpu help me? I know PP really wants a better cpu, but that is not in the cards right now. Editing seems to be fine and I am not applying a lot of effects. I do have thunderbolt 3 so I know egpu is an option. But I don't know what I am searching for to know to get something that will actually help me with render to times.

I have looked through the list of recommended GPUs for Premiere, but I get confused by the CUDA/OPENCL/Metal terms and not sure what would actually help me with render times. There are very few GPUs on Apple's list, but I have seen others on youtube use cards that aren't specifically supported by apple like the 1080ti. 

I will eventually just build a PC for video, but I want to get something that will help me for the next little bit. Any recommendations?