I’ve investigated, and it looks sympl-web-logger (which is compiled Go) isn’t being built seperately for armhf systems, so it only affects Raspberry Pi’s.
Here’s a quick workaround to compile it for the Pi, at which point it should stop throwing errors and work normally.
sudo su -
apt -y install git golang
cd ~
git clone https://gitlab.mythic-beasts.com/sympl/sympl.git
cd sympl/web
go build sympl-web-logger.go
cp sympl-web-logger /usr/sbin/sympl-web-logger
Alternatively, you can run sudo a2dissite zz-mass-hosting*; service apache2 reload which will disable the default site and mass hosting configuration.
I’ll log an issue now and should be able to push updated packages in the next day or so.