Stephen,
I am betting on Vara. The previous test you made with Vara was a real accomplishment.
The first time I ran Vara on Winlink I was amazed that it could decode stations that I could not physically hear.
For years I used a Kantronics KAM for HF packet. I always could hear AX.25 stations that I thought it should decode with no luck. I even made a test with a Behringer UCA202 sound card with the UZ7HO sound modem with only marginally better results.
Last year, with the help of John W5PSX, I built a packet station that was originally to be used for VHF. The packet part of the station consisted of a Masters Communications DRA-30 sound card and a Pi 3 computer running Dire Wolf software. This was all mounted in a Bud box.
The Vhf location fell through so I thought I would try it on HF 30 meter baud. I was amazed. I am now copying 30 meter AX.25 stations I can't physically hear just like Vara on Winlink. See stations heard directly on APRS.FI for WA5LUY-10. I have UI-View connected to the Pi computer with AGWPE. The only UI-View functionality I have lost is Acks to messages. You might want to give Dire Wolf a try before giving up on AX.25
73 and I will be looking forward to your test results.
Wayne
WA5LUY
wa5luy