hardware. If you have a 4k TV or projector tied to a Dolby DTS or Atmos sound system with thousands of dollars invested in the speaker and amplifier, then you are doing yourself a massive disservice by streaming exlcusively.
Buy a 4k Blu-Ray system and invest in physical media. If you hate having discs around, get a hardware/server based solution that can store the 4k media (terabytes worth) at the 100+Mbps bit rate.
It's not the "disc" that gives you the quality, it's the encoded format and the bit-rate, so a server could push it just as good as bluray player can.
I bought my 4k player a few years ago when Top Gun Maverick came out. I only have a handful of shows on 4k and rarely use it. But that's because my sound system isn't installed yet. Once it's installed, I'll start investing in physical media again to take advantage of the theater room.
That doesn't mean I'll quit streaming, especially on my other TVs.