It should be noted that setting Adguard as your DNS will allow Adguard to track the domains you visit. The latest info I can find is that a lot of their team is still located in Russia, which makes them susceptible to government demands regardless of their intentions.
DNS adblocking should be the last resort. On Android there are many ways to do system wide local adblocking (with and without root). Don’t know about iOS. Alternatively you can do network level blocking with something like a pi-hole.
ID tech is nowhere near flexible enough for something like Starfield or even Skyrim. It’s partially the reason why it’s so efficient. It simply isn’t fit for the task.
And the Bethesda developers are intimately familiar with Creation Engine, achieving the same level of productivity with something new will take a long time. Switching the engine is not an easy thing.
Not to say that Creation Engine isn’t a cumbersome mess. It has pretty awful performance, stability and is full of bugs, but on the other hand it’s extremely flexible which has allowed its games to have massive mod communities.