With external antennae they may have better range. From what I can find the router is 802.11ac and supports 4x4 MIMO on 5Ghz. Which is quite fast WiFi speeds. You could get an aftermarket router with 802.11ax. Which can be better on new devices which support it. Most device you have probably don't support anything better than 802.11ac and probably just 2x2 or 3x3 MIMO. Making anything faster a moot point.
Unless you are transferring large files over your WiFi between computers. Any website you visit is probably going to be the limiting factor. Not your WiFi. As long as you have a good connection.