Hello.
In case of both Shared or Host-only networks, the *.1 address refers to the internal NAT, and as mentioned its used for traffic routing purposes.
macOS host in those cases, by default has the *.2 address, and for host-only networks it would be: 10.37.129.2 you can look it up using ifconfig command in host Terminal.
As for changing it, there is no direct way to do it, although in general it's not required, unless there is a specific purpose for which that would be needed.