Which Neptune? Assuming not a Neptune TL, all the other models are frontloaders* so one wouldn't reasonably expect a lessening of lint production on another frontloader. That is curious.

*There were five Neptune frontloader models of Maytag design (MAH3000, MAH4000, MAH5500, MAH6500, MAH7500). Three (MAH9700, MAH8700, MAH6700 were sourced from Samsung. The two Neptune TL models (FAV9800 & FAV6800 were also a Maytag design and possibly produced more lint due to different action.

My 22 yr old Neptune was a MAH5500. I replaced it with a MHW5630HW, both front loaders

Lint almost always comes from the washer and the agitation of the clothes. Most drums (certainly older) were not well finished resulting in rough edges on the drain holes - mostly on the inside edges that you can't really see. As the clothes spun they would be forced through the holes and snagging casuing the fabric to tear. Those tears would break off in the dryer - that is where lint come from

I know this is an old discussion but if I understand correctly, you went from a top load agitator to a front load?

In Consumer Reports testing, front loaders are more gentle on average so I would assume that's the reason for less lint.

Out of 36 top load agitators in their current test, only 9 machines scored a 4 out 5 on gentleness. 0 got a 5.

Of 42 front loaders, 18 machines scored 4 out 5. And 4 scored a 5 out of 5.

And gentleness does not negatively correlate with cleaning power (the only test visible cleaning) so gentleness is definitely one of the benefits from front loaders.

"Michael Roberts: I know this is an old discussion but if I understand correctly, you went from a top load agitator to a front load?"

The OP said her previous washer was a Maytag Neptune model MAH5500, which is a frontloader. She replaced it with another frontloader, which is why she questioned the noticeable reduction in lint with both machines being frontloaders.