Hi @nikita2206,
I do not know why nobody is answering your question – maybe because predictions are difficult, especially when they concern the future.
What is most likely to happen if you use your Acer Predator Connect W6 with manufacturer's firmware and connect the device to the internet: The firmware (i.e. the u-boot partition) will be upgraded to the newest version (if it is not installed already). You will be able to install OpenWrt later (via the serial connection) but you will need to hold down the reset and the wps buttons during power-up to do so, and you will have to setenv bootmenu_default (and the rest of the u-boot environment) correctly to get the device to boot into OpenWrt persistently.
What might happen: If Acer releases a new firmware that prevents booting from firmware images not signed by Acer and/or using the known workarounds to manually set the actual boot partition – and if your device updates to that firmware automatically, you probably will not be able to switch to OpenWrt later. Whether that will happen is something only the people at Acer know, and maybe even they have not decided yet.