recent upgrade the plan from 800mbps to 2gbps

After market router and switch, modem remain the same Huawei(HG8240H) since 2019

my question is,
internet backbone support 2gbps but LAN ports are bottlenecked at 1gbps, speedtest will test internet backbone. Local speed cap at 1gbps.

How to solve this instead of upgrade all the device, modem, router, switch

not familiar with YTL Broadband.

But i am assuming that if YTL is using HSBB network, just like many other like Unifi, Maxis, etc., then a transfer between ISPs on HSBB  should be available (so that you don't have to release your existing port to waiting queue).