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Decent YouTube client?
(lemmy.ml)
F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device.
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What you're searching doesn't exist and will never exist.
You want to comment/interact with multiple accounts, and that can be done exclusively with the official app and the official website.
The reason is that if someone reverse engineers and spoofs a way to comment from a foss app, 30 seconds after the first release, some spambot asshole would immediately edit the code to send spam, and Google would patch that way immediately