You can inherit progressbar in progress_bar.js

add this code to set different colors in formview

do add css

.o_progressbar .o_progress .o_progressbar_complete.o_progress_gt_fty {
  background-color: #456325;
  height: 100%;
}

.o_progressbar .o_progress .o_progressbar_complete.o_progress_lt_fty {
  background-color: #000000;
  height: 100%;
}

ProgressBar.include({

    _render_value: function(v) {
        var value = this.value;
        var max_value = this.max_value;
        if(!isNaN(v)) {
            if(this.edit_max_value) {
                max_value = v;
            } else {
                value = v;
            }
        }
        value = value || 0;
        max_value = max_value || 0;

        var widthComplete;
        if(value <= max_value) {
            widthComplete = value/max_value * 100;
        } else {
            widthComplete = max_value/value * 100;
        }
        this.$('.o_progress').toggleClass('o_progress_overflow', value > max_value);
        this.$('.o_progressbar_complete').toggleClass('o_progress_gt_fty', widthComplete > 70).css('width', widthComplete + '%');
        this.$('.o_progressbar_complete').toggleClass('o_progress_lt_fty', widthComplete <= 70).css('width', widthComplete + '%');

        if(this.readonly) {
            if(max_value !== 100) {
                this.$('.o_progressbar_value').html(utils.human_number(value) + " / " + utils.human_number(max_value));
            } else {
                this.$('.o_progressbar_value').html(utils.human_number(value) + "%");
            }
        } else if(isNaN(v)) {
            this.$('.o_progressbar_value').val(this.edit_max_value ? max_value : value);
        }
    }
});
     

Probably the best way is to cusomise the css to show different colours. You can override the css by adding a static/css/mycss.css file, and include in your __openerp__.py.

If that doesnt work you will have to create your own widget by inheriting from the progressbar widget - but that requires a bit of developement and javascript knowledge.

Give a shout if you need help

Hi , 

Refer the blog:

https://www.cybrosys.com/blog/how-to-change-the-color-on-a-progress-bar-in-the-odoo-15

This blog post provides a step-by-step guide on how to change the color of a progress bar widget in Odoo

you can do it just with css and xml without using javascript :)