Not sure if I'll be able to articulate this clearly but I'll try to offer a few ideas...
My general suggestion would be to involve him more in the advanced planning of activities. Encourage him to engage in goal setting and to define what success would look like for an activity. Ask him what sort of support he'd like you to provide him with. The goal is to get him to take more responsibility and to see you as on his team not just as his boss/critic (and to be clear I totally get that you aren't being bossy or critical, but it sounds like that's his perception).
Ask questions rather than offering advice. Instead of stating the solution, note the problem and ask what you can do to help.
Another subtle thing that helped a lot here was not directing the information at him, but talking more around it with phrases like "the most common approach..." or "many people find it works to do x...". Also, asking before offering advice with something like "I can see you've come far in getting x done, would you like a hint for the rest?"
The "sandwich method" can be good. Compliment, suggestion, compliment.
Finally, and I'm sorry this has been rambling, one thing that really helped our child was learning a bit about the brain and about anxiety. Namely, that when he's upset he's not learning. He'd got to tame the upset before the brain can flip over to learning mode.
