Dynamic Par styles

As @BobLevine points out - use more styles - it's a must for clean document structure.

You're probably too deep into the layout to realise that you've encountered a situation that you want to now fix.

Luckily that's where scripts can work wonders. 

All you have to do is create your additional Paragraph Style and then add the names of your paragraph styles to the script

Replace Par 1/Par 0/Par 2 in the quotes with your own style names. 

Save the code in a plain text file and change the extension from .txt to .jsx (or grab another srcript and duplicate it and edit it and replace the text in a plain text editor).

This is rudimentary - we could add a trigger to make it run automatically - like a listen event when you Save the Document 

var doc = app.activeDocument;
var stories = doc.stories;

for (var s = 0; s < stories.length; s++) {
    var paragraphs = stories[s].paragraphs;
    for (var i = 1; i < paragraphs.length; i++) {
        var thisPara = paragraphs[i];
        var prevPara = paragraphs[i - 1];
        
        if (thisPara.appliedParagraphStyle.name == "Par 1" && //insert your style name
            prevPara.appliedParagraphStyle.name == "Par 0") { //insert your style name
            thisPara.appliedParagraphStyle = doc.paragraphStyles.itemByName("Par 2"); //insert your style name
        }
    }
}

https://creativepro.com/how-to-install-scripts-in-indesign/

What I'm thinking is that we come up with Scripts to apply your paragraph styles

Then assign Keyboard Shortcuts to your Styles - if you're using hotkeys for Paragraph Styles that's perfect we can replace those Shortcuts to trigger scripts instead. 

So if we have script that says you want to assign par1 - the script then triggers.

Let us know if this works for you - automation by scripts is awesome and a huge time saver. 

It's just 1 extra style

And we can trigger the application with Keyboard Shortcuts when applying the styles

Or simply saving the file - but that could cause mass text shifts.

So I think running the script once to apply the style as you want it to appear with the extra style will work for you. 

Then the we could build other scripts that trigger with keyboard shortcuts to apply the styles. 

Are you interested in this?
If you are drop a sample file with your styles and we can take a look at automating this for you. 

<EDIT>

Sample file and script attached (change .txt to .jsx)