The Pixel 8 and 8a aren't that expensive either. And keep in mind that they are supported until 2030 and 2031 respectively. [1] They not only receive security updates for 7 years, instead of the 5 years for previous Pixel generations, but also have stronger hardware security, by implementing the ARM memory tagging extension. [2]

[1] https://grapheneos.org/faq#device-lifetime

[2] https://grapheneos.org/faq#recommended-devices