I am running some SIMH emulators (think of them as vintage computer virtual machines) on a Raspberry Pi running Raspbian buster, and I'd like to set up networking so that a two-way connection with the outside is possible. For the record, I'm only using Ethernet (no WiFi) on a RPi 1.
In order to do that, a guide  suggests to create a tap interface to which the VM will connect, assigning it an IP inside the home network, and bridging it with eth0. However:
a) buster apparently ignores the
/etc/network/interfaces initialization routine, so I can't use the kind of config script described in the guide
b) if I set up a tap interface manually with
ifconfig tun0 192.168.1.88 up (as an example, not the same IP as the RPi), the ssh connection to the Raspberry Pi freezes and it basically stops responding to the network until I connect via serial terminal and take
So my question is, what's the most appropriate way to create such a configuration, in which the VMs running inside the RPi have two-way access to the network (at least home network, ideally also to the outside world), in a way that's also respecting of buster's conventions for init scripts?