This could be done. but is a bit of work.
Needs to handle custom filters (TACLS and CCK).
Parts would need to be stored in a dictionary to store their original category and TechRequired fields.
Then set these to category -1 or suchlike and TechRequired - hidden or suchlike if TACLS is not Enabled and changed them back from dictionary values if TACLS is then Enabled.

This should be an additional option.
Disabling TLS while keeping parts can be a lifesaver when the mod is buggy with a new KSP version.