Router to router bridge over bonded pair

I have a number of cameras that I need to connect to my home router.
I have a bonded pair set up from a Mikrotik RB493 to another router RB750 to combine the speed I need between properties.

I need the cameras on RB750 to be on the same subnet as the RB493. It has been suggested I bridge the connection.

RB493 IP 192.168.88.1/24
RB750 IP 192.168.89.1/24

So… RB493 ether8 and ether9 are bonded to RB750 ether3 and ether4
bond ip 192.168.84.1 on RB493
bond ip 192.168.84.2 on RB750

If I plug a camera into RB750 ether2
how do I bridge the RB750 ether 2 to the RB493?

No need to bridge. Just set the corresponding routes on the connected routers. If you would like to bridge you need to extend the subnet or renumber one of the subnets to join networks into one.