How Small Is Small? From PC Mag https://www.pcmag.com/encyclopedia/term/process-technology To understand how tiny these transistor elements are, using state-of-the-art 5 nm feature sizes as an example, 16 thousand of them laid side-by-side are equal to the cross section of one human hair. See half-node and active area.

Semiconductor Feature Sizes (approximate for all vendors)

      Nanometers  Micrometers  Millimeters
 Year     (nm)       (µm)       (mm)

 1957  120,000      120.0       0.12
 1963   30,000       30.0       0.03
 1971   10,000       10.0       0.01
 1974    6,000        6.0
 1976    3,000        3.0
 1982    1,500        1.5  **
 1985    1,300        1.3  **
 1989    1,000        1.0  **
 1993      600        0.6  **
 1996      350        0.35 **
 1998      250        0.25 **
 1999      180        0.18 **
 2001      130        0.13 **
 2003       90        0.09 **
 2005       65        0.065
 2008       45        0.045
 2010       32        0.032
 2012       22        0.022
 2014       14        0.014
 2017       10        0.010
 2018        7        0.007
 2020        5        0.005
 2022        3        0.003
 2024        2        0.002 ***

What this means is:- very complex circuits can be laid out and placed inside a bypass capacitor on the 3.3 or 5 volt rail that pass their data through the encapsulant via IR and also receive instructions. They can be hidden on multilayer boards hidden by the + and G rails from x-rays. They can also access data busses by similar hidden means. With data bus access they can get/send clocked data on command. Ever hear of the 'Russian Pebbles'. Dead drops that use a foot coil to send/receive data, and yes, they have wireless charging - a charger agent places his foot nearby the buried pebbles...