I respect your opinion, but personally I don't think moving to a 4-2-3-1 would result in too much of a difference. We saw what a back four looked like with these players when Heckingbottom was here with his, admittedly baffling 4-4-2, and our defense was still exposed and our attack still toothless.
We just don't have the quality out wide to make wingers work or the creativity in attacking midfield to consistently provide our one striker with opportunities. When we are able to create chances we don't have the quality up front to put enough chances away to compensate for a defence that seems to concede from half chances.
I love a 4-2-3-1, it brings a lot of versatility and you only need minor tweaks to accommodate for different circumstances. But we there just isn't the quality in this team, without those EPL loanees, to make it work.
It's not really a shape problem at the minute, it's a 'there's no quality or mental resilience' problem and changing shape just means you're moving your mentally shot and technically limited players into new positions they aren't accustomed to.