I use LibreElec on a Raspberry Pi 4, though it doubtless also works well on a Pi 5 (and the cheapest one with 1 GB of RAM is probably plenty).
It does great with local [networked] media and that's all I use it for. There's a million plugins for other things, some dating back to the XBMC days on the OG Xbox 20+ years ago, that others may find utility in... but for regular commercialized streaming I just use a $25 Chromecast and that does the business well-enough.
(LibreElec has a huge advantage to me that most people probably don't care about: My AV receiver sounds brilliant and was once very expensive [~$4,500], but it's rather old and it chokes on HDMI signals higher than 1080i. It is also unable to decode things like Dolby Digital Plus, TrueHD, and DTS-HD.
This would make the receiver a non-starter for post-Blu-Ray film soundtracks, except the Pi4 has two HDMI outputs. It is a no-effort built-in for LibreElec to use one of these outputs for video, while the other one is dedicated to high-res multichannel PCM audio.
In this way: The video system gets whatever video signals it wants, while the audio system is just fed PCM audio and doesn't have to struggle with any of that more-modern business at all. Everything is very happy with this arrangement.)
A cheap Android TV box. Between lack of proper hardware acceleration for 4K/Dolby Vision decoding and lack of sleep(!) support, I would never recommend that hardware, the ones that are actually recommended by the community are RP5 ($$$) and especially Intel Nx00 (N100 etc.) which are actually the gold standard of mainline(-ish in case of RPi) codec and hardware support.
