Quick answer = yes.
But its nothing to do with your ul/dl speed.
I am in a small village and on the max connection of 72mbs dl and about 20mbs ul, i max out at about 7mb when grabbing torrents.
I also have just over 60 wifi items not including hive (zigbee) and ST (zigbee and z-wave) sensors
This includes many wifi bulbs, 2 swithces, many plugs, 7 echo devices, Yale lock, 2 cameras, 2 laptops (one is the weather server on 24/7) 5 tablets on 24/7, 2x weather hubs, aircon, watch, phone and god knows what else ive forgot about. about 30% on 5ghz, rest on 2.4.
Now, back a couple of years when i only had about 40+ items connected, i used to have issues where devices dropped out here and there. What cured it was getting a BT Whole Home 3 mesh setup (add 2 discs to the above list) 1 connected via ethernet and 2 on wifi, each disc is capable od handly around 50 or 60 devices. so my hub was getting bogged down and thats what your problem will have been, not the speed of your interweb perse, the new hub may help if it can handle more devices than your existing hub, ideally it should be wifi6, if not, then deffo get a reasoanble mesh setup.
Leave 2.4g and 5g on, the devices will use whichever they can, if its a 5g device and cant reach properly, that device will use the 2.4g, so leave both on, after all, you reall want the best possible speeds.
Thats about as far as my knowledge extends and thats only cause ive been there
