Exporting a video will always require time to process as the video is transcoded regardless of specs. CPU and tech it has within that the software can utilize along with the specs of the output file (resolution, bit rate, color depth, FPS, codec, quality of compression, etc) will determine that amount of time.
Typically when referencing "lag" while editing I'm referencing how smoothly you can scrub through the timeline/clips and how the software is running in general. When video editing I describe lag as the disconnect felt from the video editing app and usually accompanied by me saying "Is this thing even friggin' doing anything?!". Lol.
A general rule to video editing is to use dedicated graphics. It doesn't matter which GPU your computer has just as long as it has dedicated graphics so the video editing software can move GPU driven loads off the CPU.
Resolution, codec, color depth, compression profile, and/or frames per second combined or even individually of your imported media will directly effect performance.
Without dedicated graphics results will vary however modest clips that you are recording with non professional hardware will be perfectly fine. Here is a video I made really quick on my 13" MBP i5 (no dedicated graphics), these are 2 HEVC clips (rt709), one at 1080p30 the other at 4k30 encoded.
Scrubbing through both the HEVC 1080p is fine. However the HEVC 4k clip is a bit lagging. So in that case HEVC is fine and 4k would be fine but not HEVC encoded 4k. But that isn't always the case since it depends on the specific clip. I've used HEVC 4k from an iPhone without noticing a problem and that is likely due to the complexity of the HEVC used.
Thats an extreme too, iMovie hated those clips and fought me at every turn trying importing them. In the end I had to transcode them with handbrake h265, even then there were limitations. Considering that I would say you'll be mostly fine. If in doubt just get a Mac with dedicated GPU.
