Nextcloud on 7430 AVM

Hello, openwrt has been working on my Fritzbox 7430 for a week. Actually, I would have wanted to get two things to work on it.
1: nextcloud. I found Unfortunately, the instructions are from 2014. Unfortunately, they are no longer up to date. During the installation I shot my LuCI. I wanted to use an external hard drive to store the data. unfortunately I'm doing something wrong. Is there a better guide or should I try another way. I got nextcloud working on a raspberry pi, but openwrt is a different linux than debian.
2: Project would have been an attempt to read out the data from my Power one inverter via an RS485 adapter.

Does anyone have any idea where there is a useful guide for the topics.

Greetings Michael

Ad 1.:

To sum up the first few sections: You won't have much fun on an old Lantiq SoC. I would stay with the Raspberry PI or, depending on your usage, with something even more powerful.

Ad 2.: Is there an actual question involved? Obviously, you will need a RS485 adapter (you can use a USB version, since your device has a USB port). And then you need the required software, are there any open source projects for your specific inverter? You did not name the make and model of it, so this is just a generic answer.
Usually, a microcontroller like a ESP32 is sufficient for reading RS485 data. My inverters are polled using an ESP32 with a LAN interface.

Edit: That's not a feature request at all.

Okay thanks
to 1: Thanks for the opinion. Unfortunately I installed the Raspberry 3B for something else. I have to think about it.

to 2: I have two Aurora Uno 3.6 and an Aurora Trio 20.0. All three were originally Power One and are now ABB after a warranty claim. ESP 32 has LAN? I meant they only have WiFi.

There are versions with LAN and even with PoE. I use a WT32-ETH01 board for most applications, but where I require PoE, I have good success with a Lilygo T-INTERNET-POE module (that's what I use for talking to my Hoymiles inverters).

Regarding your Aurora, there seems to be a project for ESP-based devices:

Of course, you can use an OpenWrt router for it - the following project should be able to work on OpenWrt if you port it: