I will be doing my own work,so cost irrelevant.I collect Remington Smoots .
Soldering or using a proper epoxy to hold in a barrel liner for a use such as you describe is fine, but only if the revolver will be used for relatively low pressure ammunition as it was originally designed to use.
Threaded barrels can be removed and have the breach diameter turned to a larger diameter than the rest of the liner in the bore to deal with the issues you are concerned about.
Care must be taken to leave enough room for the solder to flow, pretinning is almost a must for both pieces and care must be taken to keep the heat consistent to alleviate warpage.
Proper clearances need to be maintained with epoxy as well and the epoxy has to be applied to both surfaces before being installed. Care must be taken to make sure the liner is where you need it to be once the epoxy hardens.
The best way to allow the epoxy to cure is with the barrel pointed down. This allows for an even thickness of epoxy all the way around the liner.
Making up barrel lingers for just about any firearm has its own issues.
A liner for a 22rf rifle is pretty easy.
Once you start getting into centerfire cartridges things can and do change.
Muzzle loading rifles and pistols are also relatively easy to reline.
Your particular pistol, which has a cast barrel and frame is unusual and I am familiar with it.
I didn't do the job but the pistol I worked on had been "sleeved" by a smith from Salmon Arm, Jack Stead.
Jack knows his stuff on such things and even though he's now in his nineties, he still does some very nice work if you can convince him to do a job.
Jack installed a liner in this particular firearm using low temp solder and it appeared to be holding up very well.
The pistol came to me with the indent striker broken off the hammer.
Some of the "new" rimfire 32 ammo is HOT as you seem to be aware of because of your concerns.
The "FIX" for your concern, is to make sure you slightly oversize the forcing cone to make sure the bullet doesn't catch on the edge as it's entering. A slight radius on that edge will also help deflect the bullet towards the center.
The frame of your pistol completely covers the base of your barrel, unlike that of the pic in starpuss's post, so you shouldn't have any issues with weakness at that point, as is often the issue with centerfire pistols with sleeved barrels that aren't part of the frame.
If that were my pistol, depending on its finish, many were nickle plated, I would use a good epoxy, such as Devcon titanium or steel putty to "glue" the liner into place.
Titanium Putty has;
15,000 psi compression strength
2,000 psi shear strength
7,700 psi flex strength
.001 in shrinkage, after 18 hours of cure time.
This is more than enough strength and to hold a liner in place.
If you're at all concerned, rough up the outer surface of the liner and the inside of the barrel.
I've used this epoxy to repair threaded holes to keep machines running, until there was time to shut them down and do a full repair if required. Often as not, it wasn't necessary.