My mod is not "lightweight" and I know this. The biggest problem for me is, that the Army Size/Wealth is hidden in a lot of places in the GUI, so written in a lot of files that need to be changed. Maybe I can find another solution, I need to see. And I'm always open for hints.

But its not so hard for everyone without deep IT-knowledge to make this mod compatible with your mods by your own.
Just follow these steps:

1. Check where my GUI files get overwritten
Is the Army Size shown in the Character Window?
Just in the "Declare War" Window?

2. Look at my files
- Lets say you still see the Military Size in your "War Overview Window".
- Go into the Workshop Directory: Steam\steamapps\workshop\content\1158310\2797936557\
- Go into the GUI Folder:\gui\
- Open the file "window_war_overview.gui" with any text editor like "notepad ++"
- Search for "Maggus" because I have marked all the places in the code where I did something. Let that open in the
background

3. Look at the mod that overwrites my ".gui File"
- Now you go back to Steam\steamapps\workshop\content\1158310\ --> Thats CK3 Folder for all mods
- And you look through all the folders and see if any other mod also has the "window_war_overview.gui" File
- Back that file up on e.g. your Desktop

4. Add my Changes to the ones of the mod
Now you start to copy my changes into the file for the mod that overwrites my file. But be careful that you hit the right spots.

5. Tips
I did some extra work and for example added the religion and culture of a character to the War Overview.
This is just for a nicer look and to add some information that could be interesting instead, but its not necessary.

If you can live without that, just open the file that overwrites my mod and search for thinks like:
datacontext = [WarOverviewWindow.GetLeftSideComposition]
datacontext = [WarOverviewWindow.GetRightSideComposition]
datacontext = [WarParticipantItem.GetComposition]
text = "[CharacterWindow.GetCachedMilitaryStrengthText]"
tooltip = "[Character.GetGoldTooltipWithBalance]"
text = "[Character.GetGold|0]"
text = "[CharacterWindow.GetCachedMilitaryStrengthText]"

Or simply "soldier", "army", "gold" or something like that.

If you place a # before this text, it will be seen as a comment and not as code.
When you save that file than, the GUI will automatically be updated as long as you started the game with these parameters:
-debug_mode -develop

So you don't need to start the game new to see what your code change will bring.
If you want to be sure that the gui is reloaded, open the Console by pressing ^ and type "reload gui" without the "".
Game will stuck for some seconds and than you can be sure the GUI is reloaded.

Just play a little around but be careful to not destory the order of the { and } because that could crash the game.
But even then, its no problem, use your backup and start anew!
Don't be shy and worry about breaking the game, I've broken the game dozen times when creating this mod.