Inside the home you can usually get away just using the internal link local addresses. E.g. my main PC is fe80::10, my wife's pc is fe80::11, my router is fe80::. You can even use that when you get "fancy" e.g. my NAS is fe80::12 internally or ${public_prefix}::12 "externally" (that one actually works on either side).
This address will also run afoul with the "privacy first" randomizations on most devices by default. This addition is truly the scourge of letting IPv6 seem dead simple to use.
Don't forget that IPv4's link local addresses (169.254.0.0/16) are also randomized for the same reason: making link-local addresses use sequential numbers by default requires a centralized node to coordinate them, which is counteractive because link-local address are designed to not require one.
IPv6's answer to IPv4 private addresses (e.g. 192.168.0.0/16) is ULA (fd00::/16). Newer routers are beginning to assign local hosts with ULA addresses, thus if you want to have a stable address to a local device, you can simply connect to it by ULA.
This address will also run afoul with the "privacy first" randomizations on most devices by default. This addition is truly the scourge of letting IPv6 seem dead simple to use.