Hi there, my name is Vasia, I am lead dev at Sunstone Soft.
Actually, you are in some kind of trouble with that. Angular is well-known for being hard to optimise. I can apply several tools to your project, but I am afraid situation won't be much better.
One of the possible solutions can be server side rendering, we can discuss it.
But I also have another suggestion. Currently our team has one frontend dev who has a gap in project timeline and I just paying them salary for doing nothing :) What if I suggest you to rebuild your frontend with for example NextJs which is much much better for that? Of course at lowered rates.
I would be grateful if we can discuss some of the scenarios and start working.
Kind regards,
Vasia