How to solve hot water flow for large 5 bedroom house?

I have an old property with a gravity fed water system and a "system boiler". The hot water flow is extremely soft and so I was advised to fit a water pump to increase the flow and pressue. A salamander pump was fitted but it was extremely loud and the pump noise could be heard throughout the house despite me putting sound absorbing foam beneath it to capture the vibrations. This pump eventually failed and a new pump was fitted which is even louder. On top of this the system seems ill equipped to feed the house, there's a water tank in the loft and then a cylinder upstairs but beneath the loft that has insulation around it. To heat the water there is a gas system that uses the insulation to keep the whole cylinder warm to feed the home or alternatively there is an emersion stick in the cylinder using electricity that we can turn on to warm the water being very expensive. Could anybody please advise what might be a better way to solve the water flow and system issues please? It's a large 5 bedroom house so we considered installing a combi boiler but understand that wouldn't feed the 2 bathrooms in the house simultaneously amongst other drawbacks. Appreciate any advice, lost for ideas. Thank you!