https://openwrt.org/toh/start

Its very hard to recommend a specific product, because manufacturers keep coming out with new, low-spec versions of their own flagship devices under the same model number. Can be very frustrating to find you've bought the XXXX YY.ZZ (7) variant that has half the RAM of the (1) through (6) but costs 20% more.

Now I just go with whatever is available second-hand.