A great substitution for the leg curl would be a version where you are lying supine (on your back) on the ground, beginning with knees bent in a glute bridge position. Place your heels on a towel (lift toes up to reduce friction on ground) and let the towel slide as you extend your knees to full extension, then return to flexion (knees bent where you started). It is essentially the exact same as a leg curl. If you are looking for something more akin to a “heavy” leg curl, you can do single-leg variations (either go single-leg for just the portion that you are extending out to a straight leg [the eccentric portion of the movement] or for the whole extension to flexion movement [the eccentric and concentric phases])
If you don’t have tile, hardwood or smooth concrete, another option is to begin in a similar position (without the towel), and slowly inch-by-inch march your heel out until you hit near-full knee extension.
Here is a youtube video of the leg curl w/ towel
To your final question, I personally would agree that trying to salvage it for a few more weeks would be beneficial. But I might be biased as a strength & conditioning coach 
The fact that you were aiming for a low-load, high-velocity phase means you really won’t be that far off from your desired plan. If you were in a max strength phase, that would be a little more of a drop off