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I would start by bleeding the coolant system and see if that helps.
To bleed the coolant system, remove the radiator cap. Install the coolant bucket. Fill the bucket about 1/2 way. Then raise the front of the car as high as if it were on ramps. This way if there is air in the coolant system, the circulation brings it to the highest point. Then turn on the car, and put the heat on speed number 4, recirc mode on, and face mode. You may need to rev the engine to move the coolant around to get the air out. After you have good heat, and little to no bubbles in the coolant bucket. Then the coolant system is properly bleed. You should have good heat when bleed properly. So when you put your hand over the vent and hold it there for 30 seconds, you get a slight burning sensation. That is perfect heat.
If you can't get a coolant bucket you can make one see image.
Water pumps never really fail on this engine.
Most of the time it's just air in the coolant system
That could be air in the coolant system or a restriction in the radiator.
I would try to bleed the coolant system first
Well when you bleeding it and after you have it all set, see how it is, and then you can return if you like and I can continue to give you my thoughts on your problem if that doesn't work