I have personally been training with swords for 30+ years and there is one thing I did not appreciate when I started, but am grateful for now: my fencing coach insisted on focusing on footwork.
All I wanted to do was hit people with swords, but no, we had to do footwork drills first.
And I am so glad that she did insist. It laid the foundation for my swordsmanship career.
I took that approach with me when I branched out into other martial arts, and historical fencing: getting the movements mechanically correct and fluid has made me a much better swordsman, and prevented many kinds of injuries.
Learning these foundations will certainly improve your longsword skills. It doesn’t take much time, and it makes all the difference. If you want to run rings round your opponents, here’s how.
As with all physical skills, results will take some time, but probably less than you expect. I usually see noticeable results in students within the first class, and a general improvement in their ability to move within the first month.