Adblockers will require you to "jailbreak" your device and their installation/use will be against numerous terms of service agreements. Maybe they won't be illegal though, who knows

There could be some kind of lawsuit or legislation mandating that AR or VR platform owners provide access to third-party software (like how Microsoft was forced to offer other browsers back in the day).

A firewall with deep packet inspection and a shared database among people who block ads would be easier.

take your glasses off