As far as I know, there is no one left to work on TPHs and parts are difficult or impossible to find. The Iver Johnson TP-22 is FINE... I have owned several dozen of them and at one time they were one of my most beloved. However they are not much smaller than a Kel-Tec 9mm.
As far as the Walther PP, PPK, PPKs, etc. Because of the design, the Makarov is an improvement. The primary difficulty in ANY Walther PP series of any origin is that the cartridge must make a difficult leap, UP from the magazine into the chamber and that leads to a lot of malfunctions and ammo sensitivity.
The Makarov shoots a slightly more powerful round, the 9x18 Makarov ammo instead of the 9x17 which is the .380.
The Makarov slide pushes the cartridge STRAIGHT in from the top of the magazine into the chamber. This leads to much greater accuracy and reliability. I would not willingly carry a Walther for self defense instead of a Makarov.
The Makarov is slim, sturdy and reliable. Silver Bear, Russian ammo works in some of the Makarovs and even though it is the 9x18 it has the performance characteristics of full 9mm. Most Makarov ammo is 95 grain or close to it traveling at 800 to 950 feet per second.
The Silver Bear, 120 grain, Hollow Point, leaves those Makarovs that it works in, at about 1200 feet per second. This ammo has a microscopically larger diameter than most other Makarov ammo so it does not work in some Makarovs that have tighter chambers. In those it does work in, it is fantastically accurate and powerful.
Quik-Shoks are available at Walmart in our area. Velocitors are too and they are often very good in small .22s. CCI Mini-Mag is often a top choice as well but not always.
You are already at the top of the Mountain with Glock 19 and Iver Johnson TP-22 but the TP is ammo sensitive and each one is different. I bought dozens and dozens of them for $80 as I knew they were a bargain and thought they should have gone up to three or four hundred dollars at least because they are FAR better than the Walther PP-22s and smaller. I sold all of mine for $200 to $250 but they are back down in value now I think to a lot less than that.
The Makarov is basically a Walther that works, is more reliable, more powerful, more accurate, and a third the price or so... IF, you get a Makarov that does not like the Silver Bear 120gr HP, it will likely do well with Corbon or S&B or some other ammo... Personally, If I had a Makarov that did not like Silver Bear, I would use FMJ only in it and go for the penetration as few of the other Hollow Points open up, the Corbon is the only exception that has tested out for me.
www.Makarov.com is the Know-All web site for the Makarov.
Small and Powerful and fairly reliable; the TP-22 is fine with whatever the best ammo is for YOUR particular one.
Powerful, small, accurate, reliable, and as perfect as you can get - You have it, the Glock 19.
In between, Makarov RULES the Mountain and per my experience nothing else comes close.
Note: I am certainly NOT an expert. I just like pistols and have a long time hobby of buying, shooting and selling them - always seeking the Holy Grail. I have found that Holy Grail of pistols now and it is not one but several and you have two of them now. Consider the Makarov; German has the better finish and fit; Bulgarian is less expensive and more likely to like Silver Bear.
I have a couple of East German Makarovs for sale now if you are interested for $350 each and they DO like Silver Bear very well. You can get a Bulgarian for under $200 however and it shoots as well.
