Which Sonoff ZBDongle-P or ZBDongle-E for use as a router?

Hi all.

I currently use Sonoff ZBDongle-P (Z2M) and I would like to buy a 2nd one to perform as a router to extend the zigbee coverage.
I see there’s a ZBDongle-E variant.

Which one should I get for my scenario?

Both are good, but since you have a P, I would buy a P again. If your coordinator fails (hope not, but can always happen), you can re-flash your router with coordinator firmware and be up again in no time.

thank you.
would the E variant be of any use in the sense of future-proofing?

Both the P and E have almost the same specifications, IRL they almost perform the same.