2mm heat shrink tubing too big for thin wires inside of USB-C cable

[monster_of_electronics]

I'm trying to shorten a USB-C cable, the wires inside (apart from the power line) are very thin. My smallest heat shrink tubing is like 2mm and it's too big, even after I shrink it. Hot glue and electrical tape seem like they would make a mess. Any ideas for how to better insulate tiny wire solder joints in a spliced cable permanently or is buying 1mm heat shrink tubbing my best option?

[BreakingOhmsLaw]

You could remove the insulation staggered and use a single heat shrink.
o=solder joint. Does this make sense?

------o-----------------
----------o-------------
---------------o--------
--------------------o---

[SeanB]

Liquid electrical tape or the cheap alternative, nail varnish. Stagger the joints so that you have a single wire insulation thickness, and then paint the solder, then slip a sleeve over after it is dry, and you have given it a final coat over all the joins.