I have been considering replacing my nearly 7 year old iPhone (although very reluctant) and I was checking for options. Really the only phone that caught my eye was the Sony xperia 1 V, but I found no information about how to degoogle and lock down the device. I really like the features and the built in camera apps, etc. Is there a way to degoogle the phone without loosing the funcionality/ease of use?
The Xperia phones are often horrendously locked down and don't provide bootloader unlocks all the time.
I would definitely recommend a Pixel device if you're going to go De-Googling. That, or go select your desired ROM beforehand and buy whatever they support the best. You can find out if you look into Graphene or Calyx or Lineage as examples for which devices they support the best right now. Buy it unlocked, and unlock your bootloader.
The Xperia phones are often horrendously locked down
Not really, at least when compared to most other brands. I've had three or four different Xperia models, and unlocked the bootloader on every one of them using official Sony tools. They even have official open-source software archives, which are very helpful to people who build de-googled "ROMs".
The one thing that has been especially locked down is the TA partition, which contains DRM keys used for Sony's proprietary apps. It's not needed for an open-source OS like LineageOS.
For this phone specifically, it looks like official LineageOS support is already underway, despite it being a fairly new model:
I would definitely recommend a Pixel device if you’re going to go De-Googling.
Pixels do have unusually good support for user-installed OS, but the irony here is that you can't truly de-google them, because no OS will change the fact that Google controls the hardware and firmware.
That has been my experience with Sony phones, too. And as you (and I) pointed out, that device already has official LineageOS support so clearly it can be unlocked. I can only assume this is a regional problem or something. I know Japanese and American variants can have permanently locked bootloaders, which sometimes catches out second-hand purchasers who haven't done their research.
This is the best suggestion for this purpose. Check out degoogled ROMs like e/os/, Divest, Graphene, Calyx, etc. Find which one better fits what you want, and then get a device that is 100% supported by that ROM.
To add to this I'd also pay attention to the Android version that the OS is based on. Last I checked e/OS is a few versions outdated. GrapheneOS works very very well, you (OP) just have to understand how to set it up for your use case.