I'd go for the newest you can afford in the size that you want. The newer the device, the more years of support, the more "bang for your buck" as it will last more years. For example the Pixel 7a is $500 in the Google store, and there are 4 years of support left. This is $125/year. Pixel 8 is $700 without discounts and has 7 years of support left, so $100/year and currently is discounted to $550, so even less per year.
In my case, I have the Pixel 8 and I'm very happy with it. I'd totally recommend it.