I'm thinking I might go without PoE and just meet my current need, then add a PoE switch to support cameras if or when I get them.
That's more or less what I did when the dirt cheap AliExpress cameras died - just got a PoE switch from PB Tech and a small pile of Reolink cameras (RLC810A). Definitely the best value-for-money, and works well with Home Assistant. Way better than those stupid splitters or having a pile of individual POE injectors.
The main thing that bugs me about my Chromecast is the gradual loss of functionality over time, presumably as a part of planned obsolescence or deliberately crippling features to make you pay for premium options.
Next time I need to replace/upgrade something, I think I'm just going to skip streaming at all and just hide a full desktop somewhere and pirate everything.