Higher Definition Video editing

Hi All!

My first post here IM looking for some help.

Ive been making videos with Movie maker for 10 years plus it seems now

boy has it come a long way!

anyways I recently switched over to FILMORA because it seems to run much smoother and had to relearn everything

I shoot mainly with iphone7 and sometimes my DJI Phantom3 drone its one step lower than 4k

IM noticing the quality is suffering and Im preparing to have my PC guru buddy build me a new dedicated video editing PC

Any advice on how to render proper higher quality videos to youtube?

Are there any settings now that I could check with my current setup?

example video below

any help or advice would be appreciated before I drop $1500 on a new PC