Have you moved your cleats all the way back on your shoes? If not, do this ASAP. It can amke a huge difference. For me (and every case is different), riding was very therapeutic for me and my Achilles always felt better after a ride.
Onset of my Achilles problems was 2009. Didn’t fully kick it until 2012. Spent most of 2010 playing golf. I had honestly gotten to the point where I thought I’d never be able to run around the back yard with my kids.
What changed for me…eccentric calf raises (which you are already doing) and glute strengthening. Monster Walks w/ bands, single leg squats, Running Man poses, and many others. I had a ~45 min glute routine that I did every other day.
Swimming was also wonderfully therapeutic…
I also did one round of PRP, which helped significantly, and got me back to ~75%. The jury is still out on the effectiveness of PRP, but if you are running out of options, there is little risk to the procedure. You are just injecting “you” into you. Biggest risk is infection from the needles during the procedure, which is very small.
Did my first 70.3 in 2012 and full IM on 2014, qualified for 70.3 Worlds in 2017. Also find a good physical therapist, one who understands active lifestyle.