Please help our simple bgp

Hello Our router is running simple bgp. "one BGP router, two upstreams (each 100M from ISP A and ISP B) We are getting full feeds tables from them We discover the routes is going to ISP A only even the bandwidth 100M is full Can we set the weight to change to ISP B to use ISP B as preference routes? Can the following configuration work? What suggest to this weight no. too? neighbor 1.2.3.4 description ISP B neighbor 1.2.3.4 remote-as 111 neighbor 1.2.3.4 weight 2000 If this works, how is ISP B upstream connection is down? Can it still be failover to ISP A automatically? If it won't work, Do you have any suggestion? Thank you for your help