Solved by increasing the swapfile size on RPi 3B by adding
init_commands:
- if [ ! -f /backup/_swap.swap ]; then fallocate -l 2G /backup/_swap.swap && mkswap /backup/_swap.swap && chmod 0600 /backup/_swap.swap && swapon /backup/_swap.swap ; elif [[ ! $(dmesg|grep _swap.swap) = *swap\ on* ]]; then swapon /backup/_swap.swap; fi
in the config of SSH & Web Terminal add-on. Take a look at this github issue: https://github.com/home-assistant/operating-system/issues/968 or here in the community How to increase the swap file size on Home Assistant OS by JZhass