Replace old Webster radiator valve

2nd year in the house with 2 pipe vapor system. Replaced most of steam trapslast year. Trying to work on radiator valves before the heating season. The Webster are likely original to the system. But many are in really bad shapes. The first one is stuck on completely off position, and missing the handle to turn it back on. Tried to use pb blaster, heating it. just can't get it off from the supply pipe to service. Seems like the previous owner already had plumbers replaced some of the valves in other part of the house, like the one in the 2nd picture. They just cut the pipe and put in a regular valve. I know the old Webster stuff is special and have controls that can't just be replaced with a regular valve. But I prefer having a working radiator. If the plumber can't get it off. What is my best course of action here ? What is the closest replacement value I can get ? Thank you.