Each Wi-Fi generation is marketed on peak speed, which is the number least relevant to how it performs in your home.
What actually limits your speed
Your internet connection, in most cases. If your broadband delivers a certain speed, no router makes it faster. Upgrading Wi-Fi to exceed your connection speed changes nothing you can perceive.
Distance and walls, which attenuate the signal. A better router transmits no further through concrete than an old one.
Interference from neighbours on the same channels, which is worse in dense housing than anywhere else.
What newer standards genuinely improve
Handling many devices at once. Newer standards allocate airtime more efficiently, which matters in a home with dozens of connected devices rather than a few.
Latency and consistency, which affects video calls and gaming more than raw speed does.
And access to a less crowded frequency band, which in an apartment building is the largest practical benefit available.
When upgrading helps
Many devices competing. A crowded wireless environment. A connection fast enough that the old router was the bottleneck.
When it does not
Poor coverage in part of the house. That is a placement and access point problem, and the solution is a mesh system or a wired access point, not a faster router in the same spot.
The cheapest improvement
Move the router. Central, elevated, away from metal and other electronics. That frequently outperforms any hardware upgrade and costs nothing.