The delay usually means there is an error somewhere in the file. These are usually things like crossed lines through a pocket or vertices that are not aligned. They can be really difficult to spot. They are usually the result of bad constraints somewhere in a sketch. For instance, if you have constraints related to π, and then edited part of the tree that alters the way π got rounded it can break things in extremely subtle ways that are very hard to spot. You may not even know that π was being used internally to simplify some aspect of your constraints.

Once you know and understand this issue well, it should alter the way you make constraints to a large degree. Like, it is good practice to avoid stacking constraints across a lot sketches by importing geometry. It is better to constrain to the origin and only stack one or two layers on constraints to other geometry. It is best if you avoid constraining anything to a reference that contains infinite numbers like π. The computer's floating point registers are finite and always truncate infinite numbers.

I find it is usually faster to simply rebuild a part from scratch after I get to the point where I have made several changes in the middle of the tree and errors creep in. It is hard to make yourself do this. I feel like I don't want to "give up" on this thing I've invested so much time in. If you simply view it as a rough draft, the you will often see much faster and more efficient ways to build the part when you have a nearly completed design to work with already.

If I do not plan to share the file, I use the old file to make binders, disconnect them, and often just use these to pad and pocket as needed. It is a hacky way to do it, but it is super fast.