Goal: Setup and use pixel 10 with grapheneOS as anonymously as possible.
Threat model: avoid big tech surveillance, spyware, tracking.

Context:
I am somewhat new to privacy, I started around summer 2019 but only really got into it almost 2 months ago.
I am coming from a full Apple ecosystem.

I bought the Pixel 10 from a retailer in cash without sharing any info, in person. On the phone, I skipped through the setup to get through without provided any info. I have not inserted any sim card or turned on wifi or BT even once.

My understanding is that first per-requisite to installing GrapheneOS is to update the phone. That would require internet. My plan is to do that using a VPN.
I have 2 choices here, but maybe just 1:

Add VPN to my network/router (If suggested, I could use some resources or instructions for this as I have never done this before but do have the technical skills to do it)
Add a client to my Pixel by transferring an APK from my laptop to the phone via cable. I don't think this would work as I can't turn on the VPN until I login which would require internet. I could be wrong about this.

The VPN I plan to use is Mullvad. I am planning to trade Monero with Bitcoin on Bisq. I have never used Bisq before or bought Monero. I am open to suggestions if there is a more private or secure way.
Then use the Monero to pay for Mullvad.

Also, my big assumption is that I can download the update my phone on VPN, please correct me if that's not possible. I haven't used an Android as primary phone in 12 years.
I will turn on kill switch / lockdown mode on Mullvad VPN, so even after restart, there's no IP leak.
I am considering doing this at a coffee shop just to be safe, maybe a Starbucks wifi would likely be reliable enough.
Also, maybe I should use Orbot instead of Mullvad?

Once it's updated. I will unlock the bootlocker from settings. then follow the rest of the instructions as per website.

Let me know if there is a step during I should be careful about.

Once GrapheneOS is installed.
disable OEM Unlocking in developer options

I plan to never insert a sim card. Not a need for me. I will just Signal/Molly and if needed, my VOIP number. I am still researching VOIP apps, recommendations are welcome.

My phone usage is very minimal, I plan to use the 12 apps it comes with. And only if needed, install OpenSource and E2E apps. The app stores I plan on using are based on the GrapheneDeveloper & SideOfBurritos YouTuber's recommendations: "Graphene store > Accrescent > Obtainium > google play store anon > aurora anon > F-droid". Based on availability on the app, I would just first first to the second. Please let me know if the order needs changing.

install Futo keyboard / Open board; revoke network permissions
enable auto-reboot
disable nfc
I am deciding between Vanadium / Firefox Focus / Firefox for the browser.
make use of storage scopes under individual app settings as often as needed
Maps: OSMAnd.
Photos: Immich (eventually)
Self host apps: I am thinking about NextCloud's apps.
Banking on Desktop or phone's browser.

For the user's on the OS, I was thinking making them per corporation. So hypothetically, for all Google or Alphabet apps, 1 user account; for all Meta apps, 1 user. For reddit, 1. I don't plan to use any of these, these are just examples. I am okay with upto max 6 users, though if it's not too hard to switch, I could make more.
I am wondering if I should use owner for daily, or make a new one. Currently leaning towards making a new one for VOIP app and Signal and use that as my Daily user profile.
Somehow, I was able to move all my friends and family to Signal.

For most media and data. I plan to host on my own server. This is a project I will pursue in Dec or Jan. I don't really want to store anything locally on the pixel. So even Contacts, Calendar, Files, Photos. I want to self host, and just have 1 source of truth between my computer and the phone.

I am gonna try as hard as I can to not install Play Services at all. I hate Google now so much. And I am gonna try using websites over app. And I am always on my computer for almost everything.
Today, I was creating a new gmail account for work and now it's impossible to do it on the web. You need to scan a QR from a phone and send an sms to a +44 number.
IF I make a new account on the phone, I will get a temporary phone number from smspool's website, pay by Monero (suggested by sideofburritos youtube).

My day to day will be using my pixel 10 offline or using wifi to connect to my portable hotspot device with VPN especially when I go out. My understanding is that, it is also okay to connect to public wifi as long as I have a VPN.

My old sim card with old phone number is in my dumbphone that i will keep on for the first 2 months, for those once in a while 2FA and moving any incoming calls/text to new VOIP number. Then the dumbphone would stay off. It will always remain at home.

I am happy to edit post and add any missing details as needed. Thank you!