I used to have a Pixel 5. As somebody who uses phones minimally (<10 min average screentime per day), but still wants utilities beyond a feature phone for special use cases (maps, translate, digital tickets, public transport, NFC payments), it was about as small as I needed it to be to tuck it away in my pocket for the whole day. It was also quite a nice form factor with a black stone-like back case, which didn't seem to scuff or attract fingerprints.
I had two of them. The first one lasted 2 years before the battery swelled up and I had to dispose of it. Google replaced it for free with another. Then eventually Google Pay stopped being supported on the second, since it was a few years beyond security updates.
After that I found no alternative within the Android ecosystem. I don't want to get into Apple products (despite minimal use, I did have the phone customised so that it was stripped bare in terms of apps and notifications, and had a launcher which I preferred over Google's native design), and every tech blog talking about small phones led back to Pixel 5, or one of the ones just after which was also out of sale and security coverage.
Even though they are sold at profit, I get the feeling phones are viewed by the industry as vehicles. Get one with a big screen into peoples hands, then keep riding on the payments for games, movies, TV and web browsing that follows that. As somebody who never used my phone for any of these things, I'm clearly not important to the market for the one-off payment of a new phone every 5/6 years.
The issue I received when tapping to pay was "Your phone doesn't meet software standards". It did mention it can be due to rooting (my phone wasn't rooted) or "uncertified software" (of which I didn't have any).
I'm sure you might already do so, but I'd advise not to rely on the phone to pay going forward. For me, I was caught off guard in a shop without any other payment method. There was no warning or notification about the change until I tapped to pay at the card terminal.
I tried a few more times afterwards with another payment method as backup, and it never worked again, even after rebooting, toggling NFC off and on. I never received an email, notification or warning in the app itself. It was quite disappointing as I reckon I could have run that phone for a few more years as a minimal phone.
Google did offer me about £100 off of a new Pixel. So if this happens to you and the lack of Google Pay is a dealbreaker, I'd give that a try.