Second x-axis with non-uniform spacing

I have made a plot with two x-axes, however I am struggling to line up the x-axis.

I have some time series data (x), and an associated reading (y), each timestep/reading has an other metric (x1) associated with it.

I want to plot(x,y), and have x1 appear on a second x-axis.

The problem stems from the fact that the time step within my time series data is not constant.

I have attached some code/figure showcasing the problem, when the timestep is constant, the time series data and other metric line up perfectly.

When the timestep is non-uniform, they no longer line up.

Is there an elegant way to resolve this?

This is not a one-off plot, so I would prefer a more dynamic solution.

If you have any idea how to display the other metric besides a second x-axis, I'd be interested in that too.

close all

A = rand(100,1);
x1 = datetime('now') + minutes(1:100);
x2 = 101:200;
x3 = datetime('now');

for ii = 2:100
    x3(ii) = x3(ii-1) + minutes(rand());
end

figure();
subplot(2,1,1)

plot(x1,A,'+r')
xlabel("Time with uniform spacing")
ylabel("Random reading")

axis tight
hAx(1)=gca;
hAx(2)=axes('Position',hAx(1).Position,'XAxisLocation','top','color','none');
hold(hAx(2),'on')

plot(x2,A,'b')
axis tight
xlabel("Other metric with uniform spacing")


subplot(2,1,2)

plot(x3,A,'+r')
xlabel("Time with non-uniform spacing")
ylabel("Random reading")

axis tight
hAx(1)=gca;
hAx(2)=axes('Position',hAx(1).Position,'XAxisLocation','top','color','none');
hold(hAx(2),'on')
plot(x2,A,'b')
axis tight
xlabel("Other metric with uniform spacing")

[Scott]

I found a suitable method to add this data to the plot:

I used dataTipTextRow to add the information to each point.

So the code becomes:

s(1) = plot(x1,A,'+r')
row = dataTipTextRow('Other metric',otherMetricVector);
s(1).DataTipTemplate.DataTipRows(end+1) = row;