Hi Welcome to the forum!
I suggest you speak with a Peplink Partner who can help you specify the right devices for this project, but until you do I can share how I would work out which devices to use.
When working out which devices to use you need to think about:
- Number of WAN and LAN ports you need today (do you need POE at the branches for VoIP handsets etc)
- Will they want to use more wired WANs or Cellular in the near future?
- How fast are the WAN links? How much raw bandwidth do we need to support?
- Does all traffic need to go over the VPN or can you split VPN traffic and general internet traffic?
- How many sites now - how many in the near future?
- High available pair of appliances at the head office location?
- Will there be a disaster recovery location?
This page is really useful: https://www.peplink.com/products/balance-series-comparison-table/
So for your requirement you say 30 sites min aggregate bandwidth of 25MBps per site, with a single head office location.
The Balance 20X supports 900Mbps of LAN to WAN bandwidth and 60Mbps of Bonded VPN throughput (100Mbps if unencrypted) but only has a single ethernet WAN port (however you can add another using USB ethernet). It includes a LTE CAT4 modem and the ability to add another modem using its expansion slot. It also has integrated WIFI AP.
It only supports 2 VPN Peers so you can’t use it at the head office location nor would it have the minimum of 725Mbps of VPN throughput needed for that role either (25Mbps x 29 branch office locations).
The minimum Spec Balance for the head office location would be the B310X which supports up to 30 remote peers / sites but it only has 500Mbps of Speedfusion Throughput.
Personally I would use the SDX at the head office (300 remote peers and 600MBps of encrypted throughput)
Or if you really need to support 725MBps of VPN throughput at the head office location then the Balance 1350 (which can do 800Mbps of VPN).
Hope that helps - and do find a local Peplink Partner to help if you can.