I am looking to upgrade my home wireless. I do not need a router, I am using NanoPi 4RS. I will not need any mesh points, I can run wire to each point.
I am considering WAX220. These have small built in antenna. I was wondering if it would be better to get something like ASUS RT-AX88U Pro (AX6000) that has bigger antennas.
If I got the the WAX220, I could get more that one for coverage, 1 per room or half of the house. Would it be better to get one with bigger antennas in the middle of the house?
Should I consider an access point with 1x1, 2x2, or 3x3 antennas?
I would like to try to get the newest and fastest that is currently supported by openwrt depending on price. I also intend on keeping it for a while, I generally do not buy new hardware unless I need to.
More access points spread across the house will always outperform a single central access point. Unless the antenna design of the spread-out access points is complete garbage, but this does not describe the WAX220 (a $200 device from NETGEAR's business line).
The visible size of the antennas does not imply their actually size, once stripped off the plastic surrounding it (e.g. the antennas inside the TP-Link TL-WDR4300 are just under half as long as their plastic sleeves make you believe). Beyond that obvious aspect, the mere size of the antennas does not imply how good they are, there are devices with internal antennas that easily beat most devices with external ones.
Multiple APs (even lower-end) transmitting at low txpower and relying on a wired backhaul are (almost) always better than a single AP, but if you can't avoid that - putting the AP into the centre is usually best. More rx/tx chains (4x4) is always better than fewer (2x2), but multiple APs might make more of a difference than more chains with a single device (towards the edges of your reception).
While we'd always suggest healthy (h/w spec) margins, it doesn't make sense to plan too much ahead either and paying a premium. What's best for you is hard to judge from the outside, it really depends a lot on size of your house, building materials, how hard it is to add more APs and on your neighbours (and their tech interfering with yours'). While a farm environment with no neighbours might prefer 2.4 GHz, you might want to look into 6 GHz in a metropolitan environment.