Don’t know if it’ll cover all your use cases, but I was looking for something similar and recently got my hands on a Steam Deck. Have been very pleased with the purchase so far. To be fair, I haven’t gotten into customizing the desktop yet, but I’m sure anything’s achievable since it’s just running Arch.

Considering that original works are discarded, it’s strange how effective they’re at plagiarizing them

I’ve found EasyEffects also useful for boosting volume on sites with quiet video. Set up a hotkey to enable a compressor with gain when that happens.