My suggestion is that you understand exactly why your current machine doesn’t work for you, so you know what problems you need to solve when buying a new machine. For example, a satin stitch is what is used to make buttonholes, so it’s unlikely you were happy sewing garments on your machine without that option.
But just because you have the option, it doesn’t mean it really works for the kind of sewing you want to do now. I bought my current machine to make flags using a satin stitch because my old machine was too lightweight to handle the task.
It also sounds like your current machine has a mostly bad relationship with the presser feet you own for quilting, such as a walking foot and quilting/darning foot. Unfortunately, many even slightly older machines just don’t have the accessories that would make our sewing life easier. But many machines will accept “generic” feet if you can find the right ones. Maybe you could take a refresher class at your SM dealer when things start to open up. They may have suggestions for you.
If you can solve the presser foot problem, the other problem is the small throat space on your current machine. Believe me, I feel your pain with this. But you should first practice on small quilt sandwiches, such as 6” x 6”. That takes the available space out of equation and let’s you get a feel for walking foot quilting and free motion quilting.
If you find yourself wanting to more with a walking foot on your current machine, I highly recommend the book “Walk” by Jacquie Gehring. It really opened my eyes to what can be accomplished using a walking foot!
Best of luck.