I know these are going to seem like simple questions that google could answer, and I fully intend to do the deep delve, eventually. I'm just trying to avoid a rabbit hole at this particular moment.
So please don't waste any precious time answering any of these questions unless they're dead easy for you ...and you feel like helping a guy out.

The Question(s):

It seems that there's a heavier type of heatshrink tubing that some people like to use as sheathing on the outside of connectors, sometimes even replacing the barrel/housing. At least, that's how it appears in pictures.

1. What do you call the thicker heatshrink to distinguish it from the thinner lighter-duty stuff when searching online?
   Are there a few names to search by?
   (Sites like aliexpress can be a gongshow when looking for stuff like this, especially if you don't know what they call it.)

2. Those of you who use this thicker stuff for these purposes, are you using the kind that comes with an adhesive lining?
   Or do you apply your own adhesive?
   If so, is it just contact cement, or is it something else way better?
   Or do you generally just not bother?

3. Do you have any other tricks or tips for preventing strain from pulling it apart?
   I always wonder how much wear and tear some of the really nice looking DIY cable projects can handle. Especially for portable audio.

4. Do you recall any good sources that you learned from?

Thanks in advance for any time or knowledge you share with me.

Seriously, like I said above, keep it low effort. I'll appreciate any response.

Unless this is totally your obscure passion. In which case, feel free to totally geek out. I appreciate crazy enthusiasm, it's a beautiful thing.