You suspect that a slow return is a half-hearted one. That if you truly meant it, you would have changed everything already. That your measured pace is evidence of weak desire.
It is the opposite. The slow, deliberate return is usually the serious one. The all-at-once conversion is often the fragile one — bright, total, and gone within the season. The pace is not the betrayal. The crash is.
Slowness is not the betrayal. The crash that follows rushing is.
What grows slowly
Consider how durable things are built. Not poured all at once, but laid course by course, each layer given time to hold the weight of the next. A self built in Torah is the same. There is wisdom in the tradition about the danger of taking on more than one can sustain — about the rope that snaps when pulled too hard from both ends.
A returnee who paces himself is not lukewarm. He is building something that will still be standing in twenty years. The one who burns through everything in a month often has nothing left to show but the memory of intensity.
Pacing with a guide
But pace is not a thing to set alone. Left to yourself, you may go too slow out of fear or too fast out of zeal, and both can wound you. This is precisely what a teacher is for.
A rabbi who knows you can calibrate the climb — adding when you are ready, holding you back when you are reaching past your strength. Which practice now, which later, what your own particular pace should be: these are his to discern in the living particulars of your life. No general letter can set your speed. Find the person who can, and let him watch the road with you. That, and not solitary heroics, is how a return lasts.