Re: the relay, that depends on your needs. My impression from these sorts of "run a relay on an RPi" projects is that they're only dealing with a subset of the full firehose Bluesky's relay has to deal with - be it a shorter timeline (as you mention) or only concerning themselves with specific accounts (like the relay operator's own "following" feed, in the case of someone running a personal relay) or what have you. Pretty sure even Bluesky's relay doesn't try to drink from the whole firehose (or if it does, it's tolerant of "dribbling" so to speak; I recall a Bluesky dev blog post about how temporarily dropping posts from users' feeds is acceptable if the relay can't keep up).
Re: write traffic, my understanding is that the appviews shift most (if not all) of that burden to the PDSes, no?
Re: write traffic, my understanding is that the appviews shift most (if not all) of that burden to the PDSes, no?