I’m not sure if it really works, but you could use a pfsense appliance. pfsense is based on BSD, and balance also works on BSD. You’d have to compile it by yourself I guess, and there wouldn’t be any GUI for it.
If you are interested in this approach, there are tutorials on how to install pfsense in a virtual machine. With that you could test if and how balance would work. If it does, the link above shows some appliance-hardware which probably won’t have such issues like SD card corruption.
Edit: pfsense seems to already have a load balancer included: https://www.howtoforge.com/how-to-use-pfsense-to-load-balance-your-web-servers