Morpheus made it very clear to neo that taking the red pill was a one way trip to enlightenment. Cypher references the red/blue pill test when talking to Neo so we can assume he did the same with him. I think Morpheus is pretty clear there is no going back.

Part of the reason is that he didn't just want to live a life of pleasure... he also wanted to revert to a state of blissful ignorance, and not know that the matrix was a fake reality.

That would go against the moral principles of the ship, whose main goal is to enlighten and bring awareness about the matrix. It would be immoral for them to erase his memory even if they could.

Cypher also was extremely selfish, secretly hated the crew, and had no qualms about selling them all out for his own benefit.

He was never going to get plugged back into the matrix without the machines replacing all the nerve wires and plugs in his body, and moreover, to get placed in a pod without endangering the Nebuchadnezzar (remember Neo was picked up covertly from the icky pool after being released). Sure, in revolutions Neo and Trinity sailed across the farms without interception but that was at high speed.

Cypher was essentially groomed by the agents, and was guaranteed the high life of the top 1% of the world. Nobody else could guarantee that. There was no incentive to be open with his crew (and he would've been banished from access to the matrix, sent to work in drugery in Zion).

Like they can teach a guy king fu in seconds.

I’m sure they could be like “okay will plug you back in at the designated facility where we help people like you, we’ll wipe your memory the best we can and you’ll go back. It won’t be exactly the same but if you commit to forgetting and we scrub what we can… in time it’ll taste like stake again. I empathize with those feelings and I’m sorry you choose the matrix but we understand. It’s actually pretty common around here”

I feel like admitting that would have led to him getting a bullet in the head.

The machines obviously aren’t interested in reconnecting him - they grow humans by the thousand in their facilities. Like you’re not going to hike for a day to pick up lost carrot when you have them growing in your garden.

The only way the machines would consider reconnecting him would be as part of a deal for something significantly more valuable than one human. If Morpheus is on the table? Sure, now that’s worth it. Which isn’t to say they wouldn’t have betrayed and killed him once they had Morpheus anyway. Our only assurance that they would honour an agreement is a throwaway line from the Architect at the end of Reloaded.

And if there’s no going back, what does a terrified resistance do when one of their fighters starts talking about joining the enemy? He’s too dangerous - he’s gotta go.

OP, you mentioned Mouse as an example in a comment. You’re on the right path - it would have been trivial for Cypher to program (or have Mouse program for him) a mini Matrix where he’s uber rich and everything he wanted. Of course, it would get old real soon.

I reckon Cypher would even have mentioned it a few times to people… things like “man, I miss meat” or “man I wanna be rich af”. Most would have taken his words as just bluster. Others would equate it with Mouse’s actions - a coping mechanism or just a temporary relief.

But the reality of it - only the machines control the real Matrix. Only they decide what gets in and out, barring a few hacks like the one that got Neo out and the others out.

To plug a full fledged human back in would require quite a lot of work. As the mania of wanting back in would have gripped him, Cypher would have left clues back in the Matrix and the machines, as someone else said, would have groomed him to betray.