Ah, OK, so looking for hobby use.
Apartments and CB's are a challenge.
CB's use frequencies in the 27MHz range, and the wavelengths are around 36 feet. For an antenna to be efficient, you'd be looking at starting around 25% of that length, or what's referred to a 1/4 wave length antennas. So efficiency in your antenna comes around the 9 foot mark.
Without an efficient antenna, your radio will really suffer from poor performance. You can shrink the antenna by shortening them and adding coils at the base, but that can only go so far, and efficiency will suffer. Trying to get 9 feet of antenna down into a 18 or 24 inch package is really going to be disappointing.
The CB radio dealers are often more interested in selling you stuff and making a profit than making sure you get something that works.
I don't like to see that happen. It's easy to spend a lot of money on hobbies only to find it's not going to work.
With the antennas you are looking at, you will be quite disappointed. Adding in a city location, it's going to be even worse. The inefficient antennas will make your signal very weak and your radio will not transmit or receive very far. Given that there are not a lot of users on CB, a weak signal, short range, and lack of people to talk to is going to create a lot of frustration.
A larger antenna -may- help, but I wouldn't expect miracles. If you can place a magnetic mount antenna outside your apartment, maybe on top of an air conditioner or metal railing, you might get a bit better performance. Take a look at a magnetic mount mobile CB antenna and see what you think. You can use that while at home, and still take the hand held out with you when you go hiking. The antenna would connect directly to the top of the radio, but you'll need an adapter:
https://www.amazon.com/SO239-Female...d=1&keywords=UHF+to+BNC&qid=1590672295&sr=8-4
For an antenna, take a look at a Wilson K-40. They are a basic mobile CB antenna that seem popular with CB'ers. You can get them with a magnetic base.
But still, don't expect much from this setup. For use in your home, range will be limited by your antenna. When using the handheld, range will be greatly limited by the short antenna on top of the radio.
There are also not a lot of people to talk to. CB tends to be short range in most conditions, so unless there is someone close by on the same channel, don't expect to hear much.
If you are looking for other options, don't overlook GMRS or amateur radio. Amateur radio can be an expensive hobby, but it has more options and often more people to talk to.