Which Wi-Fi access point (router) to choose?

Question

Computer networks

Good day dear.
Recommend a Wi-Fi access point or router for a slightly higher than normal home network.
(Please tell me the model)
Networking:
Networking is carried out by wire (IPoE with a static address) on the ZyWALL USG 20, then from it to the home server, PC and access point (now deceased). Always connected to the access point * 3 laptops, 1 raspberry pi (TV set-top box function) and 3 smartphones. Up to 3 laptops and 5 smartphones are occasionally added**.
* often connected at the same time
** to existing devices increasing the number of connected and used devices
The vast majority of equipment is only capable of operating in the 2.4 GHz band, 2 laptops have modules with a 5 GHz band.
Location conditions: Panel 3-room apartment, maximum line-of-sight distance of 20 meters (due to poor location of the equipment). Obstacles in the form of three concrete walls (with doorways) and furniture.
What is required from a future access point (router):
Required:
High-quality coverage of the described territory
Stable network operation on devices connected to it
Ability to distribute IP addresses to connected devices from a DHCP server raised on ZyWALL USG 20
Have WPA / WPA2 encryption
Ensure compatibility with existing equipment
Desirable :
Ability to connect an external drive and share it over the network (FTP/FTPS, SMB, SFTP?)
Creation of an additional access point (virtual/guest)
BitTorrent client with a web interface and/or specifying a folder for storing .torrent files.
If it's good, but it doesn't play a big role:
Print server
Air congestion control and auto channel change
Priorities for other categories (in descending order): reliability (so as not to die quickly) - price - brand - additional functions.
A separate issue is the expediency of supporting IEEE 802.11ac and, in particular, MU-MIMO.
Thank you in advance for your answers (constructive criticism and private options are welcome)

Answer 1

To burn through the space, you can take Ubiquiti NanoStation or PicoStation. But I wouldn’t put it by the bed and you can make a tinfoil hat (well, in general, the power is configurable).
Also as an option to take a pair of Mikrotik AP series. Well, or one RB.
PS
It doesn't work much as a torrent, but why the hell?! Moreover, there is a home server.

Answer 2

zukheli work well with external media. But it's better to take home nas. We definitely need normal ac support, and not 300 megabits over the air. If there is only one wall, then it is still normal. More than two means seamless roaming or a repeater will help you.