domain based blocking systems are nice for a base level of ad removal, they do nothing if the ads are coming from the same domain. sponsorblock is nice, but it’s the work of volunteers to remove those ads - if youtubes userbase were splintered over thousands of apps it wouldn’t be feasable.
i don’t know when i have seen just text-based ads in the last 10 years. those are an non-issue, even for me. the issues are scripts, user profiling and tracking.
the big difference is: the browser gives webpages/apps a standardized environment where the user has the last word regarding what runs on it or not (if you are not using chromium anyway). in apps, the user doesn’t have that luxury, especially regarding tracking and profiling.