OpenWrt with mwan3 power up and reboot issues

I an using openwrt 22.03.2 with mwan3.
When powering on or rebooting openwrt it seemed to get rather lost, which could be corrected by maually restarting the network followed by restarting mwan3.
Looking at the log it seem that some wan interfaces were attempting to connect before the system was ready i.e before br-lan was up.
To try an work around this I set wanb and wanb6 to 'Not started on boot' and added this to /etc/rc.local

\# wanb6 seems to need something extra running before it will start cleanly.
\# it seems to start best if is ready to go as wanb connects. Hence wanb6 than wanb
( sleep 30
  ifup wanb6
  sleep 5
  ifup wanb
  sleep 30
  ifup wan
  sleep 20
  mwan3 retart
) &
exit 0

Can you suggest a better solution?
Is this a common problem?

If you disable mwan3, do all interfaces start properly at boot or reboot.

What is the best way to disable mwan3?

service mwan3 disable ; service mwan3 stop; reboot