Glückwunsch, siehste geht doch 
The following things you should do now
- Update to v19.07.3
- This should be the update (please check again): https://downloads.openwrt.org/releases/19.07.3/targets/ipq40xx/generic/openwrt-19.07.3-ipq40xx-generic-avm_fritzrepeater-3000-squashfs-sysupgrade.bin
- Install TLS for HTTPS
- opkg update && opkg install luci-ssl-openssl
- Install WPA3
- opkg update && opkg remove wpad-basic && opkg install wpad-openssl hostapd-utils
- To make sure that all post-installed packages are available again after an update, I have written the following in "Scheduled Tasks"
- 0 0 */7 * * opkg list-installed > /etc/config/installed.packages
- To remember everything and also to save the files I changed, I have entered the following under System -> Backup/Flash Firmware -> Configuration
## This file contains files and directories that should
## be preserved during an upgrade.
##Install TLS for HTTPS
# opkg update && opkg install luci-ssl-openssl
##Install WPA3
# opkg update && opkg remove wpad-basic && opkg install wpad-openssl hostapd-utils
##Install Wiregard
# opkg install kmod-wireguard luci-app-wireguard luci-proto-wireguard wireguard wireguard-tools qrencode
# RESTORE using:
# opkg update
# opkg list-installed | cut -f 1 -d ' ' | sort -u > /tmp/currentpkg && cat /etc/config/installed.packages | cut -f 1 -d ' ' | sort -u > /tmp/oldpkg
# grep -v -F -x -f /tmp/currentpkg /tmp/oldpkg > /tmp/inst
# opkg install $(cat /tmp/inst | sort -u)
# rm /tmp/currentpkg /tmp/oldpkg /tmp/inst"
## FOLDERS
/etc/wireguard/*
/etc/crontabs/*
/etc/dropbear/*
/etc/profile/*
/root/*
## FILES
/etc/sysupgrade.conf
/etc/TZ
/etc/banner
/etc/config/installed.packages
- To be able to edit the VLANs of the switch via the LuCi WebGui you have to adapt the file /etc/board.d/02_network.