Hi,
I'm trying to figure out how to set up a service like pi-hole and one of the prerequisits seems to be to have admin access to the router to make the correct DNS entries.
Unfortunately, the router provided by my ISP doesn't grant me access to these settings - is there a way around that, and what would it involve? I do have a hybdrid router (DSL + LTE connection), that's (according to my ISP) the reason DNS settings are locked.
I think your best bet would be to buy your own router and then use that one instead of the ISP provided router.
If you want to go more deeper, you can maybe choose one that is supported by OpenWrt.
You can use the Table of hardware or the firmware selector to check if your desired router has OpenWrt support.
Definitely this. If you're absolutely sure you can't change config on the router, then you just treat it like a modem. Let it serve up one, single DHCP lease to your own router and run your network off of that.