[OnePlus 5 ROMs, Kernels, Recoveries, & Other Devel] Pho3nX:
Seriously? There any connection with the rom itself if you want others apps instead of stock in this rom. Maybe you should also stop to use crap app like SD Maid lol

First choice when you do a clean flash is already to install your rom with a custom GAPPS installation for add all your apps and remove directly apps that you want replace (with the gapps-config file)

for exemple it's my AEX gapps-config)

Include

# Pico+
DialerFramework	# Install Dialer Framework
GoogleTTS	# Install Google Text-to-Speech (Micro+ on 5.0-, Pico+ on 6.0+)
PackageInstallerGoogle	# Install Google Package Installer

# Nano+
BatteryUsage	# Install Device Health Services (7.1+)
FaceDetect	# Install Face Detect library for photo apps
FaceUnlock	# Install FaceUnlock
Search	# Install Google Search (excluding excludes GoogleNow and PixelLauncher)
Speech	# Install Offline Speech Files

# Micro+
CalendarGoogle	# Install Google Calendar
ExchangeGoogle	# Install Google Exchange Services
Gmail # Install Gmail
GoogleTTS	# Install Google Text-to-Speech (Micro+ on 5.0-, Pico+ on 6.0+)

# Mini+
CalculatorGoogle	# Install Google Calculator
ClockGoogle	# Install Google Clock
Messenger # Install Android Messages (except on tablet devices)
TagGoogle	# Install Google NFC Tags

# Full+
Drive	# Install Google Drive
Chrome # Install Google Chrome Browser
Drive	# Install Google Drive

# Stock+
ContactsGoogle	# Install Google Contacts
DialerGoogle	# Install Google Dialer (see warning about DialerGoogle below)
KeyboardGoogle	# Install Google Keyboard
PrintServiceGoogle # Install Print Service Recommendation Service
StorageManagerGoogle # Install Google Storage Manager
Wallpapers	# Install Wallpapers

# Super+
ActionsServices	# Install Actions Services (9.0+)
Translate	# Install Google Translate
DMAgent # Install Google Apps Device Policy

Prevent automatic Stock removals

Remove apps (uncomment a line to remove the app)

CalculatorStock # Remove Stock Calculator (automatically removed when Google Calculator is installed)
CalendarStock # Remove Stock Calendar (automatically removed when Google Calendar is installed)
ClockStock # Remove Stock Desk Clock (automatically removed when Google Clock is installed)
Email # Remove Stock Email Client
ExchangeStock # Remove Stock Exchange Services (automatically removed when Google Exchange Services is installed)
Gallery # Remove Stock Gallery (automatically removed when Google Photos is installed)
KeyboardStock # Remove Stock Keyboard (automatically removed when Google Keyboard is installed)
MMS # Remove Stock SMS (automatically removed if Android Messages is installed)
PicoTTS # Remove Stock PicoTTS
PrintServiceStock # Remove Stock Print Service Recommendation Service (automatically removed when Google Print Service Recommendation Service is installed)
SimToolKit # Remove Stock SimToolKit
SoundRecorder # Remove Stock Sound Recorder
StorageManagerStock # Remove Stock Storage Manager (automatically removed when Google Storage Manager is installed)
TagStock # Remove Stock NFC Tags (automatically removed when Google NFC Tags is installed)
Terminal # Remove Stock Terminal

(AEXPapers)
(AmberAccent)
(BlueAccent)
(BlueGreyAccent)
(BrownAccent)
(CandyRedAccent)
(CyanAccent)
(DeepOrangeAccent)
(DeepPurpleAccent)
(Gallery2)
(GreenAccent)
(GreyAccent)
(IndigoAccent)
(JadeGreenAccent)
(LightBlueAccent)
(LightGreenAccent)
(LimeAccent)
(LiveWallpapersPicker)
(Messaging)
(OrangeAccent)
(PaleBlueAccent)
(PaleRedAccent)
(PinkAccent)
(PurpleAccent)
(RedAccent)
(TealAccent)
(Terminal)
(YellowAccent)

It's really usefull for always install/update your rom exactly with your choices

In the latest Android versions, especially Pie, system/vendor apps are often protected (priv-app) by some permissions (and latest security patch). After that you can always remove an app if you want.

Just use TitaniumBackup or Swift Backup for freeze/delete them, if you can't or apps back after reboot, you must check the path of your app (in titanium) and remove all that you want in TWRP. Mount system partition, Advanced > File Manager > system > app / priv-app

Finally, my advise is always to prefer freeze an app instead of remove/delete app. It's more usefull especially when you will dirty flash for a future rom update, your rom will be updated without redo all your stuff again and again. By freezing apps, apps will be updated/erased but not active, by deleting apps the next time you will update rom all your removed apps will come back.

PS : [MENTION=5366380]quake73[/MENTION] edit your Title with "6.1" :D