Distance will play an important factor, and MU-MiMO (Multi User- Multi IN, Multi Out) For example, if you have a large home/apartment and your router is tucked in a corner in the back left and you are trying to connect over 5Ghz from the front left, you're gonna have a bad time, and a range expander can only do so much as repeating a signal for streaming or gaming can/will result in poor performance depending on your configuration. Some of the better wifi options that are available these days are:
Asus RT-AC86U
TP-Link Archer C5400 v2
Either of those will cover a standard apartment/home without too much difficulty provided you aren't trying to do what I described above. If you need a whole home coverage solution, look into Mesh networking with something like:
Google Wifi
Netgear Orbi
If you have more questions, let me know