What is the maximum number of WiFi clients on the TP-Link Archer C2?

I have a whole range of devices based on the ESP8266. On top of that the router - TP-Link Archer C2 - also supports other devices (smartphones, printer). Recently I lost the readings from one ESP that controlled a boiler. I was already about to take the chip apart, check the power supply, when my wife told me she had a problem with our WiFi network this morning - however, she changed to a different one (same Archer, but 5GHz network, which has a different name) and everything started working. I had already had a problem with the SMA inverter - unable to connect. I thought it was a distance issue, but I noticed that after restarting the SMA still nothing, and after restarting the router everything works. The router has generally good reviews (it doesn't hang) so I started to analyse another problem - the number of simultaneously connected clients. I searched the internet for this - no information on the number of simultaneous connections for C2. I found somewhere that Archer C6 has max 15 clients per band (2,4 and 5 GHz). Here is my question, have you guys encountered this problem?

This router does not actually work as a router, but as an AP. DHCP is on the other router that is connected to the internet. This second router is also a TP-Link, but an Archer C9. It is further away, but my 'boiler' ESP can see it - so it is now connected to the Archer C9's WiFi network. Back to my C2 - unfortunately I didn't check the WiFi connection stats (how many there were when the trouble occurred). Later when I analysed the problem (after moving the ESP to another network) there were 13 connections at 2.4GHz, so close to that limit with the C6 (15).

I thought the topic of the number of WiFi clients would attract more interest. After all, IOT is very often WiFi based and it can happen to anyone that another device doesn't want to join the network anymore. I asked a question to TP-LINK support and found out that "The recommended number of simultaneously connected clients to the Archer C2 router is about 15-16". I'm not quite sure what "recommended number" means, but I assumed that with more clients it wouldn't work. I also asked a question about the Archer C9 - there the recommended number is 25 clients. So I decided to get rid of that C2 and buy a typical AP. I chose the TL-WA1201 model. From the support I learned that "The maximum number of simultaneously connected wireless clients with the TL-WA1201 is 64 per WiFi band". This number is sufficient for me. Interestingly TL-WA1201 is "only" an AP, but its price is 100zł higher than the router, which after all still has a built-in switch. The AP has been working for a few days, so it is difficult for me to assess it, but there are no problems.
I do not close the topic, maybe others will comment on it.