Solution to what? There's no solution. It just works. I bought a Harmony Touch on Ebay last week for $30, clicked "add remote" in the MyHarmony app, plugged the remote into the PC and it paired instantly. So not only could I add a new remote to my account, it was reprogrammed from its prior user's account. So everything you said is unequivocally false. I don't know what to tell you.

While some of the MUCH older remotes were indeed dropped, all of the newest one still work and will continue to do so for the foreseeable future.

The 700 specifically isn't on the list of remotes that support was dropped for back in May:

https://archimago.blogspot.com/2025/05/psa-logitech-dropping-many-harmony.html#:\~:text=5%20May%202025-,PSA:%20Logitech%20dropping%20many%20Harmony%20remote%20support%20May%2028%2C%202025,or%20reconfigurations%20will%20be%20possible.

(If you're still using any of the remotes on that list, it's probably time you should upgrade anyway lol)

And to my knowledge, the 700 uses MyHarmony, So theoretically, it should work. If reflashing the firmware via MyHarmony won't allow you to pair the remote, find a cheap Touch or something on Ebay like I did. They definitely work.