Most importantly of all, OpenWrt device must be able to wirelessly connect to AP and share the internet connection on its own network (even if just via LAN in case of using Mesh WiFi). The link between OpenWrt and AP is the key.
Which router would be the best for this use case?
Thanks in advance for your help!
What I've already tried:
I've managed to get OpenWrt installed on an Archer C50v4 but it was unstable and upload didn't work correctly no matter what I've tried
I've researched many potential devices but still can't determine which one to get
I am afraid that in such an environment you won't be able to achieve better speeds with 5GHz, due to low penetration through obstacles.
You should consider some point to point link with directional antennas, if laying down a cable or using powerlines is not possible.
I would expect to get at least 100Mbps via OpenVPN (it shouldn't be the bottleneck in the connection). If it's not possible, I'll just setup VPN on all the devices. It'd be great to have it on the whole network though.
Also, if one device won't be able to also rebroadcast on 5GHz, I'm happy to get another access point. @trendy
Most importantly, I need a device which will reliably connect to the target AP and be able to share that internet connection on its own network.
I have a couple of spare routers (non OpenWrt) which can act as access points so perhaps that's the only option.
In this case, the most critical requirement is just that this OpenWrt device (maybe not even OpenWrt) has a strong enough radio to connect to AP reliably. I think for this even C50v4 was fine but just had issues.
fwiw, Linksys routers such at EA6350v3, and I think EA7500v2, have built in wireless bridge mode (and repeater mode), but you cannot use the same 5 GHz radio for both the bridge and as an access point. I can't comment on reliability and signal strength through thick walls.
Wireless communications is two way so the quality of the wifi provided by your internet connected router is just as important. (eg. is the 'receiver' deaf as a door post, perhaps due to poor antenna design, and so cannot hear your wireless devices through thick walls ?). In the past, I've read buying a pair of dedicated high end AC1750 or better Asus routers was way to go if you wanted reliable high speed wireless bridge link - this was before general availability of mesh systems such as BT whole home wifi system and Netgear Orbi etc.
For 70+ mbps openvpn, you'd be looking at £100-£200 routers btw.
Look at a CPE such as the Nanostation AC loco to make the link to the AP. These have a directional antenna which is good for point to point use. I assume you don't own the AP so you can't do much about its performance or location.
As others said you need a lot of CPU for 100 Mbit OpenVPN, this would be best done in a separate box from the wifi client.