Growing pet is a serious thing, so I'd like to keep the data on the cloud. That being said, if requested many times, then a version without registration is definitely fair.
My competitors include other social media post schedulers (e.g. Typefully) and I believe the market size is huge, since there're at least 20 schedulers on the market (didn't do the math, but enough for an indie hacker project IMO).
I want to focus solely on Bluesky, which is the competitive advantage since most of the schedulers do cross-platform posting, and cannot focus too much on a single platform.
I use screenbars (BenQ, Mi, etc.) and found them extremely helpful, in terms of reducing eye strain and leaving spaces for other desktop setups (I currently have no lamp on my desk).