I'd recommend starting with shorter intervals and gradually increasing the duration as you build up your tolerance. For example, try 3-4 x 400m at threshold pace, with 200m active recovery. Also, don't forget to warm up and cool down properly to avoid injury. It's all about consistency and patience, so don't get discouraged if you don't see improvements right away.
I've worn compression socks on and off for a few years, and I think they're helpful, but not a game-changer. They do provide some extra support, especially on long runs, but I'm not convinced they're worth the hefty price tag. That being said, if you're willing to splurge, they might be worth a try.
I've had my fair share of Achilles issues too. For me, the key was to reduce my mileage and intensity, and focus on strengthening my calf and ankle. I did a lot of eccentric calf exercises, and also worked on my foot strike and stride to reduce the stress on my Achilles. It took time, but it worked. Also, don't underestimate the power of rest and patience!
Happens to the best of us!
Been doing yoga for 2 years, noticed significant improvement in flexibility and fewer injuries.