good_moleman_to_you

That's exactly how I use my PC.
165Hz 1440p 27" G-Sync
60Hz 1080p 24"
 
I really have no issue with the mismatched sizes and resolution. Only pain in the ass are the issues with G-Sync as its pretty much impossible to play games in windowed/borderless mode if you have secondary monitor with lower refresh rate than your G-Sync monitor.

ok well i think i can relate to all of those options so here goes:
first off what are you mostly using them for ? from where your focus for the upgrade is im assuming gaming.
so since you are already running 2 monitor you already only game on one and id say having mismatched monitors isnt that bad. for the longest time i had my old 24" 1080p and a secondary 19" 5:4 1280x1024. sure those arent that far off but the 19" had water damge and the bottom 100-200 pixels werent usuable so yeah but as a secondary totally fine by me. so if you really want a secondary screen then go get a bigger main i guess.
 
but i also now have a 1440p ultrawide and i must say its awesome as a experience and i really wanted to make my desk look cleaner but from time to time i still plug in my tablet as a secondary monitor so i do miss it a little bit 

Personally use a PG278Q as my main monitor and some cheap 1080p 24 inch as a second monitor. Personally I don't really have any issues with them being different resolution and size but obviously any surround config is not going to work (I use my 27 inch for gaming and the 24 inch for other stuff like TS management music and stuff.). So I'd say go for a 1440p144 IPS Gsync monitor and keep one (I'd keep both because I like screens :D) and buy some kind of an arm to free some desk space.

Cinebench does have a GPU Benchmark, however, it's a useless one, since it focuses on OpenGL.
 
This says NOTHING about your GPU performance.
 
Use Firestrike, Superposition etc. You should get kinda double the points there.

I wouldn't worry about being embarrassed, everyone starts somewhere. For GPU I'd use game benchmarks, Furmark and 3D Mark.

Any reason why the cinebench scores for my GTX 1080 are almost identical to my GTX 970?
 

Cinebench is a CPU test, try running a GPU test like Unigine Heaven, Valley, Superposition, or similar

its got a opengl bench too,though its not very intensive and is not very helpfull.
his screenshot shows the fps and not the cpu score
 

Any reason why the cinebench scores for my GTX 1080 are almost identical to my GTX 970?
 

It looks like it is on your motherboards QVL list as only running at 2933, so I would try that with the timings listed on your DRAM sticker.
 
Also you can make sure the VSOC is up at 1.1 V which may help stability.  
 
This video has is a cool and informative talk on overclocking RAM on Ryzen by an AMD engineer.