Forty users are going to have multiple devices which is different than 40 connections. Still wireless connections are going to be weak on the wireless side. If they are anything like my granddaughter she uses 3 devices. As she is using her desktop she has her iPad running zoom and her iPhone to text with. There would be a lot more devices than 40.Any contemporary home router can easily handle 40 users. It's not the 1990's any more.
40 concurrent wireless users might be another matter but the OP has just stated that most of the clients are connected by Ethernet.