Use of non-amd jquery plugins with requirejs without modifying them?

I recently searched a lot on use of non-amd jquery code with requirejs but couldn't find a proper way to do it.

To be more specific, I want to use pana-accordion.js found at below mentioned url.

https://www.jqueryscript.net/accordion/Horizontal-Accordion-Slider-Plugin-with-jQuery-Pana-Accordion.html

But the problem is that it is not amd aware and nor it exports anything out of it.I am currently doing it for magento-2 cms.So far I have created my custom.phtml and called it on homepage through admin area.Below is my custom.phtml

<div class="pana-accordion" id="accordion">
  <div class="pana-accordion-wrap">
    <div class="pana-accordion-item" style="background-color: #F44336"><img width="500" height="300" src="https://unsplash.it/500/300?image=57" /></div>
    <div class="pana-accordion-item" style="background-color: #2196F3"><img width="500" height="300" src="https://unsplash.it/500/300?image=49" /></div>
    <div class="pana-accordion-item" style="background-color: #4CAF50"><img width="500" height="300" src="https://unsplash.it/500/300?image=39" /></div>
    <div class="pana-accordion-item" style="background-color: #FF9800"><img width="500" height="300" src="https://unsplash.it/500/300?image=29" /></div>
  </div>
</div>


<script type="text/javascript">
    require(['jquery','panaaccordion'],function($, accordion) {
                accordion.init({
                    id: 'accordion',
                });
    })
</script>

And Here is configuration for pana-accordion.js javascript module in requirejs-config.js

var config = {
    'map': {
        '*': {
            'panaaccordion': 'js/pana-accordion'
        }
    },
    'shim': {
        'panaaccordion': {
            deps: ['jquery'],
            exports: 'accordion'
        }
    }
}

Below is some code lines for pana-acordion plugin

var accordion= {
    init: function(options){
        var that=this;
        options = $.extend(true,{
            expandWidth: 500,
            itemWidth: 100,
            extpand: 0,
            autoPlay: true,
            delay: 3000,
            animateTime: 400,
            borderWidth: 1,
            autoPlay: true,
            deviator: 30,
            bounce:"-50px"
        },options);
    .....

As you can see, it doesn't wrap code inside define() nor it exports or return anything.Rather accordion object is declared globally.

So far I have following questions (those marked as bold sorry for bad formatting but I am trying to improve it).

If I wrap the code inside define like below,

  define(['jquery'],function($){
            //pana-accordion plugin code
            });

Still, there is an error in console that says Uncaught TypeError: Cannot read property 'init' of undefined, even though I created exports entry in shim configuration. But error resolves when I finally write return statement after accordion object.

return accordion;

What is the purpose of using shim, if we have to manually write return statement from plugin for object for example?

Second, Do I have to write whole path for shim configuration? If I map alias panaaccordion for file located at 'js/pana-accordion', still I have to use 'js/pana-accordion' for shim configuration otherwise there are some loading order issues.

Third- Can I use such non-amd plugins with requirejs without modifying a single line from them?? If yes, How?

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