There’s an option to enable it
Preferences → Views → Article View → Allow selection
Idk much about the ad blocking features but fluent reader seems to also lack it
https://github.com/yang991178/fluent-reader/issues/444
RSS Guard seems to support adblocking Built-in Web Browser & AdBlock — RSS Guard documentation and javascript disabled in their lite version which had an addition request open here RSS Guard. But I didn’t understand what @anon63378630 meant by “Eh, I was expecting some security focus by the name, but no it looks like the opposite.”