You need to run this script in the browser console to unlock all the settings -
https://gist.github.com/tpoechtrager/766140c49a711a2177820ea42556de3c
I don't have the router plugged in as I'm still waiting for the simcard, but you just enter the PCI,EARFCN of the tower, and it will lock to only that tower, but you have to know that when you set a lock, and that tower goes down, it will not bounce back to another one unless you reset the router.
You can find it on
https://www.cellmapper.net/ but I have also noticed that is outdated, you will need to check the PCI,EARFCN when you are connected to the appropriate tower, then set it. I allows you do to many things, including specifying bands
View attachment 1906347
This is not from mine but its similar to this