@Kdubs1981 re the central heating system.
When we bought the house, it had a single pipe / single loop central heating system with big round pipes, mostly at skirting level in each room and, importantly, visible. It was possibly original - though all the rooms did also have fireplaces - but certainly wasn't much newer than the house. It had those big cast iron radiators that old schools often had.
So when we replaced it with a modern 2-pipe system, and a new boiler (the old one would have been more at home in an ocean-going liner), we were replacing visible pipes with visible pipes and that felt fine. (Our plumber had done the same in his own house, and part of his sales pitch was for me to visit his own money-pit mid-restoration!).
Upstairs, there is very little visible piping - basically an up pipe and a down pipe from each radiator into the floor, which is normal.
Downstairs, for each radiator in the 'configured as when we bought it' part of the house there is a pair of pipes coming down the wall together for each radiator. They're painted to match the walls, and the plumber was a real artist in copper piping so they are straight, parallel and blemish-free. Most are in corners.
Where rooms have been more extensively refurbished - kitchen, bathrooms / toilets - the pipes have been re-configured and more conventionally buried in the walls behind new plastering as part of the process (which always post-dated the original re-plumbing and came once we were certain that all was exactly where we wanted it).
It's not a solution that would work in every house - it would be unusual to replace conventionally 'plastered over' piping with visible piping - but in a house that already had highly visible pipes it was entirely acceptable to us visually and made it possible to do the full replumbing and reheating as part of the 'first sweep' of renovation.