I’m not familiar with tor, but isn’t it possible to run it on a pi and route traffic through it? This way nothing would leak. Are there any disadvantages of that?
Sure, and you can configure it as a wireless router with a different SSID from your main network. Connect to it when you want to use Tor, then go back to your main network when you want better throughput/latency/jitter and you don't want half of the internet to treat you like a bot.
Apart from using Tor, you can route your DNS to avoid your ISP, which makes sense in a world where ISPs have your name/address/bank# and use what they know about you to make money.
You'd probably be sending out a lot of information that can be used to identify you (telemetry, logins, other fingerprintable info about your system). Just using Tails seems like a better option.
