Best Gear for ARC?

I wasn’t sure if this should go under Support or Audio Gear talk. I use Apple gear, including an Airport Time Capsule, a 2018 Macmini and an iPhone 6s. My Airport Time Capsule is connected to McIntosh Integrated Amp via USB. I’ve been able to test ARC out and I like it very much. The only problem is I’ve been only sporadically able to use it. I live in a semi-rural area, and don’t always get the best cellphone coverage. I’m on 4G. But even when I get all four bars on my phone, ARC will usually time out and tell me I have a poor connection. I’m using an iPhone 6S. I should mention that I use Quboz often and have had very good success connecting to their service. Is there better hardware that I should be using to reliably use ARC? Thanks for any input, Andy