You might ask the electrician what the cost would be to add a modern dedicated line for your system, assuming no other "hazards." Our previous house in NY was from the 1780s and it was expanded from a 4 room river cottage to a very large house over the course of centuries. There was all kinds of funky wiring in the house-- one of the missions of the electrician was to clean up unused wiring and replace stuff that was critical- so a lot of the kitchen appliances got dedicated lines- not something that was required when the last round of renovations was done. We did not replace everything, but a lot. My system worked pretty well in that grand old house. Obviously, prices for parts and labor have gone up since I did that circa 2003.
When I moved to Texas, the house we bought had been fully restored- an 1880s Queen Anne. The infrastructure was circa 2004 so it wasn’t "Old-Old" but I still was concerned about the quality of the juice. I had a commercial electrician come, had the city pull the meter to make sure the meter block was not corroded, and worked from there. Fortunately, I was working with a more modern wiring scheme, but did a fair amount of upgrades (using commercial electricians, who I found understood the needs of us crazy "sound hounds").
Prices for work obviously varies depending on locale. I’m very happy with where I’m at at this point-- whole house surge, big Iso transformer to feed the main hi-fi, I use point of use surge on the appliances including computers, routers, etc. Did do a whole house back up generator which involved some planning to keep the ATS separate from the circuit feeding the main hi-fi (I don’t have that big system supported by the generator- the last thing I’m gonna do in a power outage is worry about playing music). One can do this incrementally. I call it a ’system audit" and it may be worth getting a couple different electricians to visit to give you a sense of their knowledge. I found some comfort in knowing that not only the audio system is well supported, but that the entire house checks "OK." The "audit" part did not cost a lot--getting the city to pull your meter may be more involved- but where I am, they came within a week of making the request. All the work was permitted and approved. I know code is basic minimum, and I do like overkill, but doing it according to the local code as applied is important for insurance purposes.
Good luck, ground loops suck.