If you are not an illustrator, or at least willing to tweak illustrations to fit your purpose, yes, you need to actually use the clips provided by one specific vendor.
There are some online tools like www.vyond.com (former GoAnimate) but it can become pretty expensive if you do not use it very often.
An interesting program is What was at some time Crazy Talk Animator, but is now Cartoon animator https://www.reallusion.com/cartoon-animator/default.html it has some built-in characters, but you need to buy some other models if you want to change the style, or you can create your own. Both options add to the price.
You also can use free programs like Blender and Inkscape with great results, but you need to invest in the time to actually create the assets yourself.