Yes, that is my understanding as well. A PM only improves a slow heartbeat, and an implanted ICD can help with some arrhythmias, but it has to shock you, which I hear/read is a most startling and unsettling experience. I have had four cardioversions. No. 1 didn't work, and I got the third shock just as I was emerging from the propofol depths, which was NOT a pleasant experience!! No. 2, about 15 months later, lasted 16 hours, No. 3 was the next day, lasted 4 hours, and the fourth, the day after that, lasted 20 minutes. They sent me home with more metoprolol and said good luck. It converted about two hours later.
You may be aware already, by the sound of it, that you are in pretty good shape in terms of the evolution of this disorder; you're still quite apparently paroxysmal, which is THE place to be when deciding what to do next. In my experience, and in the right experienced EP's hands, an ablation is going to be the 'gold standard', as the medical community seems to feel these last few months.
I'm far from being expert on the topic, and I'm a lot newer than many to the subject and the experiences of tachyarrhythmias. Would you consider going over to affibers.org forum and registering and asking some pertinent questions there? One denizen, susand, has a storied life behind her (you wouldn't believe it), starting when she was a little girl (lived for year or more in a hospital to get her over a heart defect), and she has gone through the tide of arrythmias, over 50 cardioversions (!!!), several ablations, and is now on a PM as of about 2023. She's still not doing so great, but you might get some important help from her....if you are interested. The is easily the most resolute and toughest person I know this side of The Veil.