There are quite a few phones that will let you unlock the bootloader, but pixels are the only ones with decent security record and ability to self-sign builds f

There are quite a few phones that will let you unlock the bootloader, but pixels are the only ones with decent security record and ability to self-sign builds for verified boot. Pixel 1 will stop receiving support in a year. So you need to make that call if you want to buy a phone with just a year of security updates left.