They probably haven't upgraded to wifi 5 and wifi 6 capable access points for all of the ships. They could probably benefit from additional access points (in the staterooms).
Routers, switches, and APs may be due for replacement (EOL?). Yes, Cisco is expensive.
How often do they reboot the network components (not sure what their logs or other monitors are showing re: issues)?
Are they current with firmware upgrades (don't need to be at the most recent but fairly current)?
You can throw greater bandwidth at poor infrastructure / IT practices all you want but that's only part of the equation.