Just another suggestion. When I was first trying free motion quilting and my machine was higher than table, I went to
store that sells thick foam board like used for insulation in homes. Measure the height of your machine and look for foam that will give you an even working surface. I needed two layers to get right height. For ease of movement t covered foam board with heavy clear plastic. Most foam board comes 4x 8' and can easily be cut to size of your table or some places that sell it will cut it for you. I also used a chair I can raise higher so as to not have strain on shoulders and upper arms.
You have already received many suggestions, so hope you will try some or decide if you feel they would help and have success i doing free motion quilting