The Pixel 5 isn't supported anymore. The Pixel 6a still has a little less than 2 years of support left. These have become pretty cheap.
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]