I've been tossing a ball to certain genres and themes, failing miserably so far. Then, after replaying Harpoon 3 and re-reading Red Storm Rising (worth reading) - followed by some long hours within Supreme Ruler 2020 - I decided to write military story. However, contrary to the real-life politics, I am willing to set story entirely on Alternative Earth Universe (not necessaily actual continents and geographical regions), given the semi-futuristic-yet-modern level of technology. The WW2-ish technology would be doable as well, given these two actually do attract my mind and interest.
However, when it comes to technology, I'd like to avoid remodified descriptions of real life planes (vide Ace Combat, in which F-16 or Su-27 were used no matter the country), creating a rather unique equipment, perhaps ressembling the actual technological aviation and naval wonders, as well as technology used by mere troopers. However, I need some tips onto how to describe newly created stuff and make sure there wouldn't be inconsistencies or making things too OP.
So far, I do not plan to do all the planet's political map - most likely focusing onto local conflict between two or more political entities - giving more sidenote information to the reader within the story.
It sounds like you want to write a fictional military treatise rather than a story, or even some form of documentary.
As for creating new tech I'd suggest starting by answering the following questions:
What is it for? - Why is it needed? - Who would be using it? - When would they be using it? - Where would it be used?
Try to keep the subject basic, so instead of a rifle think weapon, instead of car think transportation. After that you need to apply cultural and technology limitations, followed by access to resources and finally size of the nation. (E.g. Smaller nations tend to focus on better training for their smaller armies where larger nations having a larger army would require faster training.)
On the flip side, if you intend to do a story (character focused) then its generally best to be vague with your descriptions to allow the reader to fill the void with their own imagination.