Possibly the phone has a somewhat less sensitive WiFi radio than the Nexus it replaced. If your home WiFi network is kinda marginal, a slightly less effective WiFi radio might expose weaknesses in your network you never noticed before. You might be able to get satisfactory performance by optimizing your network.
Of course if the phone struggles with WiFi everywhere, then changing phones is the only option to fix this.
But if the problem is basically only when on your home WiFi, you can either trade the phone for one with a little better WiFi performance or try optimizing your WiFi network for better performance. Obviously, the second option is cheaper.
So, is WiFi a problem everywhere or really just at home?
Do you want help with improving your home WiFi?