Please apply the fix from #3383 to the version 5.11.13.
As mentioned in that thread, tools and nano-saber in this vertion have about 2k durability. Can confirm that with advanced tooltips enabled (F3 + H), durability is shown after at least one mob hit:

You can download a preview build to fix it:
https://github.com/TechReborn/TechReborn/actions/runs/13115104697
(Download Artifacts and unzip the TechreBorn-5.11.3.jar)

Thank you very much :)