In reply to David Bennett.

Is there a way I could extract the blocks I want, keep them and remove the plugin? Would reusable templates enable me to do this?

Technically yes. However, it would require a bit of programming chops and knowing what you need from the plugin to make the specific block(s) that you want work. On top of that, you'd still need to add it to a plugin of some sort so WordPress still runs the code.

Reusable templates only work when the code is there to run.

Generally speaking, it would just be easier to keep the plugin intact. That way, you also get any future updates, improvements, or enhancements.