The arms race has already been on, for some years, and it isn’t pretty. Name any major antivirus vendor, and you have your pick of low-priced, relatively easy to use, ‘crimeware’ kits that run circles around them.
I don’t speak as an Elite Security Expert; but among workaday IT/sysadmin types, it’s gotten to the point where we don’t even bother trying to ‘clean’ an infected system anymore, and count ourselves lucky if antivirus software even warns us. We do sometimes inspect a system in greater detail before paving it flat, for forensic purposes and to provide samples to our vendors and try to mitigate future attacks and attacks on others; but we don’t even pretend that we are half as smart as the bad guys are.
Your average domestic-violence perp is probably dumb as a rock when it comes to computers; but the weapons you can buy are so far ahead of the defenses you can buy that that hardly matters. Once you add the possibility of physical access, social engineering or control of account information to gain control over ‘cloud’ services, customer service password recovery, etc. and possibly some violent coercion if subtler tactics fail, it’s game over man, game over.
In situations where ‘just nuke from orbit and start from clean media’ isn’t an option(don’t want to give up an email address/contacts, limited knowledge, partner retribution if a tap unexpectedly goes dark, etc.) you are talking a nation state/reasonably high end security contractor level problem.
There are some useful takeaways: “Webcam LED exhibiting any odd behavior? Odds that it’s a bug? Close to zero. Odds that it’s a problem? Alarmingly high. Nuke it to hell, yesterday.”, “Do you now, or have you ever, shared passwords, password recovery data, accounts, credit card numbers, etc. with somebody you are now experiencing togetherness problems with? Change it. All of it. Now. New passwords, new answers(preferably false and not trivially obtained from public biographical information) to security questions, revocation of any and all Oath or equivalent access delegation, warnings (if the company will accept them, and if not, why not?) that you have a persona non grata likely to try social engineering attacks against you specifically, wipe whatever you can, scorch the earth.”
The situation is hugely lopsided, though.