You've applied to 400 jobs and had 3 responses and no success to be blunt your option about what you need to do to get hired is worth zero.
You refuse to change anything about your process, you aren't working to improve it, you are arguing against people telling them you don't need to do common/standard things.
This thread is a pretty good insight into why you are failing and what you need to work on.
Like I said, i had a legit linkedin account before i closed it and it never felt like it did anything for me. I have changed plenty about my process, from cv iterations and reviews, ai assistance to cater to job posts in cv and cover letters, etc. Of course i think all the information is great, but i also have first hand knowledge and experience. If you think all that's missing is a furnished LinkedIn account then i can tell you that it isn't accurate - in my experience.
I have a couple dozen open roles right now, at a 50-person company. Each posting gets thousands of applications. Most are fakes, or AI-generated, or AI-generated fakes. Realistically, we're going to respond to 1%, maybe 2% of them, because again, 50-person team. Half the time, you get someone named Ralph McGuinness on for a quick code screen and they have a thick Mandarin accent or something equivalently implausible.
The best first filter we have at the moment is to programmatically toss out any resume that doesn't have a LinkedIn, that has a hallucinated LinkedIn that doesn't resolve, that resolves to a name that doesn't match the resume, that has no connections or history, etc.
It's an absurd state of play that hurts those of us trying to hire and those of you trying to get hired, but also a trivial hurdle for you to clear, so stop arguing and just do it.
Of those 400 applications, my LinkedIn profile was viewed 16 times. LinkedIn is not as essential as everyone is trying to portray it. Especially outside of the US where people actually care about data privacy.
LinkedIn only shows you authenticated viewers. You have no idea how many automated systems have filtered you out because you didn't include a link in your resume/application or because, as you said, the account has no connections or activity.
Do you know of any such automated systems or are you just making that up? I've never heard of application systems or ATS that looks for a linkedin URL in PDFs, extracts it along with employment information and validates it against what's in the resume, or a form that validates that a given entry leads to a valid LinkedIn profile, and that the profile corresponds to the one that was submitted. Recruiters; yes, and those will show up - and they haven't.
Every job I've applied for in the last two weeks has asked for a LinkedIn link on the application. I have more interviews this month than you've had in three years.
Just saying.
I hate LinkedIn too but i very much consider it an important part of the "finding a job post pandemic" game.
to put it bluntly, the game has changed. what you knew from before is not correct now. if you keep applying your previous intuition and experience to a job search in todays market, you are going to be in for a hard time.
You refuse to change anything about your process, you aren't working to improve it, you are arguing against people telling them you don't need to do common/standard things.
This thread is a pretty good insight into why you are failing and what you need to work on.