[Google Pixel 2 XL Guides, News, & Discussion] Nikos2k:
Yes, just as your running of flash-all.bat script in both slots would do

The rom.zip is the zip file of any custom rom you want to install

For example, for the pixeldust that you installed, the rom.zip file would be the PixelDust-X-aosp-taimen-20200114-1015.zip

If the file transfer doesn't work, the usual suggestion is to try with another cable, on another USB port, or on another PC

But since you say that giving ADB commands works, I do not know what could be wrong

Do you have another PC available to try the file transfer connection ?

But you are ok for now, you have a fully functioning rom (except the file transfer), right ?

I don't use TWRP backups either as sometimes they don't work.

Badger has indicated a way to backup through adb commands:

BACKUP: adb backup -apk -shared -all -f <filepath>/backup.ab

RESTORE: adb restore <filepath>/backup.ab

https://ww.9to5google.com/2017/11/04/how-to-backup-restore-android-device-data-android-basics

For a PIXEL 2 XL rom that is fully featured (it has every customization that you can imagine), I would propose Havoc OS

But keep in mind that it is an Android 9 rom and it is no longer up updated

(but still it is better in features than any Android 10 rom, but you do not have the monthly security updates)

You can find the latest zip (August 2019) here: https://sourceforge.net/projects/havoc-os/files/taimen/

(Havoc-OS-v2.8-20190807-taimen-Official.zip)

You will have to install latest Android 9 factory image: https://developers.google.com/android/images#taimen

(9.0.0 (PQ3A.190801.002, Aug 2019))

I use Google Backup and Titanium Backup

Some data are obviously backed up through the google account (photos, contacts, gmail, calendar, google drive files, chrome bookmarks, keep notes, list of android apps etc)

Google Backup saves some device data such as call history log, sms messages, wifi passwords

Before flashing a new rom, I would also do the backup of the chats in the messengers as WhatsApp/Viber that are not fully cloud based such as hangouts/telegram etc

Then you have the apps settings. The problem is that not all developers use the recommended android API to save all app account data, customization and preference settings of the apps.

So I save all the apps data with titanium backup and restore them if their data are not included in google's backup

Make sure especially that you backup the authenticators apps data

Yes, keeping stock rom is less work

(but if you install Havoc, you will not want to go back to stock :) )

But for a normally maintained custom rom, there is usually an update within 10 days after the monthly security patch is released by google.

Yes, usually the custom roms do not have OTA updates. So the usual way to update them is to download the new rom.zip file, and flash it.

You have also to download the new vendor.img of the monthly update and flash it too (I described the way in the previous email)

Instead of flashing the vendor.img, you can flash the whole monthly factory image but with the "-w" switch removed (so that userdata are not erased), if you think that some other components of the factory image have been improved (for example the radio)