Any polite, constructive advice, folks?

Yeah.

Get yourself a "ball valve" the size of copper pipe from your water meter
and while the water is off, just cut out a section of pipe and put in the
1/4 turn ball valve. The ball valves cause very little pressure drop (they
are even better than gate valves.)

An inside whole house water shutoff is all you really need althought it's
"nice" to be able to isolate the hot water heater and still permit water for
the toilets.

Again, with compression fittings you don't have to worry about soldering.
The water meter shut off may not be 100% leak tight. The compression
fittings work even when there is water present. Make sure you have proper
sized wrenches on hand and just tighten enough to stop leaks.

You might be able to get a valve that uses "O" rings to make the seal.
These usually can be installed without wrenches (hand tight will do; some
just require that you insert the pipe into the end and that's it!)

It's up to you whether you trust plastic valves or want to go with brass
with a stainless "ball."

If you insert plastic parts in a metal water line, you may want to ensure
that you have an electrical connection around the plastic part. Many
older homes use the water pipe connection for the electrical "ground."
(Today, it's standard to place two ground rods.)