Should I upgrade to Mojave or higher?

Hi there,

I'm using a 27-inch, late 2013 iMac with the following specs. :

iMac (27", Late 2013)

macOS High Sierra Version 10.13.6

Processor - 3.2 GHz Intel Core i5

Memory - 8 GB 1600 MHz DDR3

Graphics - NVIDIA GeForce GT 755M 1024 MB

As you can see, it's currently running High Sierra (10.13.6) I'd like to know if it would be safe to upgrade to Mojave or any of the higher versions. And if so, which OS would be best for me to upgrade to.

I usually run adobe illustrator, photoshop and occasionally final cut pro. I have occasionally faced lags and crashes before but it wasn't really a regular occurrence. I recently cleared some storage and now have 230.89 GB available of 999.35 GB. I'd just like to make sure I'm getting the best possible performance from this system. On a trivial note, I'd also like the dark mode that comes with Mojave but if staying on high sierra would be a better option I wouldn't mind it.

This is my first time posting on this forum so I hope I've done it right! Please feel free to guide me as to how I can provide any additional information that would help answer this question. Thank you!