I’d look into MongoDB Atlas for the database itself and Google Cloud Storage or AWS S3 for storing images and videos with the link to their sources stored in the database.
Lemmy being decentralized doesn’t make it very search engine friendly. Because it’s federated across multiple instances, none of them reach a critical mass big enough / trusted to be constantly at the top of results. Duplicated content across instances can be flagged as spammy content.
You should be able to do that with a ublock origin filter.
Maybe ask on the community: !ublockorigin@lemmy.ml
When using a browser they can get your user agent (https://www.whatsmyua.info) They can also get some information about your device, like pixel resolution, screen size (https://www.whatismyscreenresolution.org), gpu (https://hardwaretester.com/gpu) etc…
All of those data combined make a fingerprint for your browser, that can be more or less unique.
I recommend having a look here for more information about how fingerprinting works and how to protect from it, and to see how “unique” your browser is (https://coveryourtracks.eff.org).
When using an app, it’s a whole lot more complicated to escape from it, but one step I can recommend, is to delete your phone advertisement id (https://www.eff.org/deeplinks/2022/05/how-disable-ad-id-tracking-ios-and-android-and-why-you-should-do-it-now).
That been said, from my own reddit gdpr export, it doesn’t look like reddit is doing any fingerprinting of that sort. I haven’t looked so close at it yet, however.
On the frontend.