I haven’t tried OpenVPN, but I would be curious about the performance. Although it’s a small CPU, it does have some crypto extensions that might aid with OpenVPN/tunnel performance. Here’s the lscpu output, which shows that the CPU does have AES and several checksum extensions, so OpenVPN performance may not be too bad.
[root@host ~]# lscpu
Architecture: aarch64
Byte Order: Little Endian
CPU(s): 2
On-line CPU(s) list: 0,1
Thread(s) per core: 1
Core(s) per socket: 2
Socket(s): 1
Vendor ID: ARM
Model: 4
Model name: Cortex-A53
Stepping: r0p4
CPU max MHz: 1000.0000
CPU min MHz: 200.0000
BogoMIPS: 25.00
Flags: fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid