The problem with omni tools is the swiss army knife effect. to more stuff you cram onto something, the worse each component becomes. That’s why the only really useful part of a swiss army knife is the toothpick. the knife is ok, the scissors next to useless, the corkscrew pretty good at impaling your own hand, etc.
If a tool had infinitie functions, they would all have near zero capability.
Perhaps nanite colonies that change shape on demand could solve that, but they would have material strength limits that might make them too flexible when rigidity was required, etc.