Is it possible to disable ip forwarding in AP mode ?

Several threads here voice frustration about network isolation in AP mode.

Because SXR requires IP addresses on each network it is not secure without network isolation enabled but enabling network isolation breaks external routers ability to control traffic.  Thats fine for guest isolation but kind of sucks for lan <> IOT or admin <> employee where finer grained or one-way traffic control is desirable.

Is there some way to instead just disable routing / forwarding e.g. make:

echo 0 > /proc/sys/net/ipv4/ip_forward

persistent ?

For my IPV4 only network that does everything I want but using telnet to set it each time router is rebooted kind of sucks.

I can think of cases ( untrusted guests ) where client and network isolation is still desirable but I can't think of an AP application where forwarding is appropriate.