As long as only ADSL is required, the WAN speed (and with that the maximum expectation for VPN tunnels) is limited to 20 MBit/s (and <16 MBit/s in practice), this is easy to accomplish with lantiq hardware - without hardware AES.
For ADSL Annex A the best option would be the BT Home Hub 5 Type A (read the wiki before buying, the initial flashing is a bit involved and it might make sense to buy a device with LEDE preflashed), you'll find them for <10 GBP with the vendor firmware and ~25+ GBP for preflashed devices.
For ADSL Annex B the AVM Fritz!Box 3370 (rev 2!) might be a pretty good option for ~25 EUR.
Both devices will support VDSL2 up to 100 MBit/s (with flow-offloading enabled, hard at the limit, but possible), VPN won't work at that performance levels (at all), but sufficiently for <= 16 MBit/s (as in ADSL).