Yeah. The interactivity in this new universe of uifigure is still too slow. The simple solution is to use de old Matlab figure. Don't forget to create properties in your app to handle the figure and the axes.
You could do something like this...
% Declare two new properties of your app.
properties (Access = public)
fig = [];
ax = [];
% Create a function and call it during the startup of the app.
function startup_figCreation(app)
app.fig = figure;
app.ax = axes(app.fig);
end