If I use an external drive will it help speed up my iMac?

Allan I appreciate you taking the time to answer me, but I think you are wrong. In spite of your advice, I bought a Licie SSD and am using it right now. It has sped up my 2019 Imac considerably. In fact, I'm now enjoying my Imac again, because the speed has increased so much. Before, I was ready to throw it in the garbage, because it was so painfully slow. Trying to use word, excell and other apps were almost impossible. It would take 2-4 minutes to load one page. Now I click on any of the apps and it loads immediately. It's like I got a whole new computer. I have no idea if I have fusion or anything else you said (I'm not tech savy) but I think I bought my computer in a year they were switching things over and ended up with a dud. All I can say is, it worked for me!

Thank you Jack, I did buy one and am using it and it has made a huge difference. Thanks for the advice!