Those are not codecs that need a super fast workstation.
When do you need your workstation?
Computex starts 27 may 2019 and some important announcements will be made.
For displaying 10 bit color during color grading you need one of these
https://www.blackmagicdesign.com/products/decklink/models just pick the one that fits your needs.
The current fastest GPU for Resolve is the $700 AMD Radeon VII with 16 GB of 1 TB/s memory.
You need 2 displays, 1 for color grading(color accurate) and 1 for editing(lots of workspace).
Get a scratch drive of atleast 1 TB (samsung 970 PRO for example).
Get atleast 32 GB of memory, when you also work a lot with Fusion get at least 64 GB.
When you edit/grade a lot for content that will be shown in the cinema a 4096x2160 screen might be worth buying, otherwise get up to a 3840x2160 screen, these a way cheaper with the same quality (we grade on calibrated LG OLED TV's or Samsung QLED for high brightness enviroments).
What are your storage needs, do you have a NAS or do you want storage in your workstation.