That sounds frustrating. I do not own your radio, but I don’t want your question to go unanswered. There is a guide Troubleshooting Digital Modes – digirig which gives a step-by-step approach to isolate and solve each problem.
There is a thread discussing IC-718:
Thanks for posting the photos of your setup. Is your Digirig configured for CI-V output rather than logic or RS-232 levels? You can see more discussions about IC-718 here:
https://forum.digirig.net/tag/icom-ic-718
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