Selective network access point using wireless bridge

I'm not sure if the title makes a whole lot of sense, but my current set-up is that I have one device that is acting as an access point for a couple of other IoT devices.

The IoT devices connect to the access point over wlan, while the access point connects to the internet over a cellular connection and provides the IoT devices internet access through a bridge in /etc/networking and hostapd (as well as providing some management functions). The cellular connection is metered because the normal data flow rate is very low (kB/day)

I would like to be able to intermittently connect my laptop to the access point over wlan, but once I do this, the various stuff on laptop will start using MB of data for updating or syncing or whatever.

Is there a way that I can configure the access point to ignore packets from my laptop that are trying to make it to the internet while still allowing the IoT devices access?

If you don't mind to do a manual command you could set your default route 0.0.0.0 to the loopback adapter on your laptop (or simply delete the 0.0.0.0 route)

That would allow you to talk to the IoT device, while any packet matching the default route will be dropped from your laptop side directly.

Do a route print inside your laptop and check your route.

From there if your IoT device are in a LAN, like 192.168.100.X, then you add a route to there via the wifi bridge IP.

You need to know the bridge IP that face you, and the subnet used for your device.

route add 192.168.100.0 mask 255.255.255.0 192.168.X.X -p

-p to make it persistant if needed

After that do a manual route;

route delete 0.0.0.0 to just disable your Internet.

route add 0.0.0.0 mask 0.0.0.0 127.0.0.1 if Windows is recreating your default route to the access-point.