There's a Systemd-related MAC spoofer you can install, tho I dunno how reliable that is.

OP is specifically asking about spoofing MAC address on an Android device. Systemd is not part of Android.

You can apparently change the Android MAC via the terminal emulator:

• with root access: busybox config [name of network interface] hw ether [new mac]
• without root access (will reset at reboot): ip link set [name of network interface] [new mac]

What is the problem with Whonix or why no one's talking about it? I thought it provided better security than Tails..

It's fine to talk about it. Isn't the default download for Whonix a pair of Virtualbox virtual machines? Not trying to argue which is the most bestestest security, but that is quite different than a regular disk image, like Tails, so they're for different use-cases, aren't they?

Whonix is Debian-based so you'll still be running Systemd if you consider that an issue. While Virtualbox is itself (mostly) free, it requires a non-free compiler, so that's something to consider as well.