Well one thing is to provide light, warmth, and leave it the **** alone. It can't form roots with you doing things to it all the time. Believe it or not, plants do know how to grow all on their own. You provide growing conditions and nothing else.

Exactly. The thick basal plate is a problem with old bulbs. There’s no need to touch a newly bought bulb. All you need to do is plant it and water it. You are overthinking this and probably causing the non-rooting by constant fiddling.

Do you think that it will still root, and if so, how long?

I have no idea. I’ve never messed about with one as much as you have. All you can do is be patient and stop tormenting it.

Actually, a 3/4" thick basal plate is quite thick and really does need some trimming so I think you made a good choice on that. I'm a bit shocked you were sold a bulb with such a thick plate. But anyway, now all you have to do is just leave it sit for a while. Weeks even. Bulbs that have been trimmed take longer to get their roots going, but it should be worth the wait. And some bulbs are just slower to get going every year. I've noticed that about Picotee (5 weeks since potting, it's still just sitting there, I know it'll come eventually because it does this every year), whereas Blooming Peacock is almost always the first one to kick up leaves and flowers. Maybe your Minerva is like my Picotee.