router – Need Help on Designing Network in Warehouse

I need help on finalizing the Network Scheme for a Warehouse.
Current System has 2 different ISP with total 6 wifi access point for 3 each since it’s large Warehouse
Each ISP has 3 WiFi access points for connectivity.
In current Schenario, If a ISP goes down users has to manually connect to another WiFi.
We want to get rid of this architecture and implement single WiFi with 3 Access Points so if any ISP is down a switch changes the ISP automatically so users don’t have to change the WiFi.
They are always connected to same WiFi Network.
I tried reading for SD-WAN but not sure if it’s a good idea.