Falcon ideally you want something still in production, if not plausible then the 4a/4a5G are your targets, the 4a5G shares more in common with 5th Gen than 4th and could receive longer than minimum stated support.
Check here for more info:
https://endoflife.date/pixel
If you are looking at the best VFM (Value for Money) option then the 6a is hard to beat as you won't need to spend again in a years time, you actually won't need to spend again for a minimum half a decade.
The Pixel 6a is a budget device with the same 5 years of guaranteed full security support from launch as the flagship 6th generation Pixels. It also has the same flagship SoC as the higher end devices, the same main rear and front cameras as the Pixel 5 and a rear wide angle lens matching the flagship 6th generation Pixels. Compared to the 5th generation Pixels, it has 5 years of full security support remaining instead of less than 2 years and the CPU is 2x faster. We strongly recommend buying the Pixel 6a rather than trying to get a deal with older generation devices. You'll be able to use the Pixel 6a much longer before it needs to be replaced due to lack of support.The Pixel 6a is a budget device with the same 5 years of guaranteed full security support from launch as the flagship 6th generation Pixels. It also has the same flagship SoC as the higher end devices, the same main rear and front cameras as the Pixel 5 and a rear wide angle lens matching the flagship 6th generation Pixels. Compared to the 5th generation Pixels, it has 5 years of full security support remaining instead of less than 2 years and the CPU is 2x faster. We strongly recommend buying the Pixel 6a rather than trying to get a deal with older generation devices. You'll be able to use the Pixel 6a much longer before it needs to be replaced due to lack of support.
Source: https://grapheneos.org/faq#recommended-devices