So everyone tells you to exclude your device on Smartthings before migrating to hubitat.
That advice is correct, except that it doesn't actually work at all in my experience. This applies to all manner of zwave devices. Some devices I can add to Hubitat after a factory reset, but many devices simply refuse then as well.
I don't have a zwave protocol analyzer, but I did spend 10 years running a IOT lab where we debugged things for companies like AT&T, and I have been a smartthings user for nearly all of that time. I have 4 different smartthings hubs, as well as many other popular hubs. None of them hold a candle to Hubitat, and I'm throwing all of them away... but I digress.
What I think I have found is that Smartthings does not correctly exclude zwave devices. So don't even try, it doesn't work at all. It is the correct thing to do, but only if it works. I don't know what smartthings is trying to do, or why it doesn't work, but that doesn't matter, it simply doesn't.
You don't have to exclude from the device it is paired to, it can be excluded from any device that has a working exclude mode. One popular zwave exclusion device is the Aeon Labs Z-stick... But wait! Don't run out and buy a Z-stick unless you are a pro that does this for a living. The fact is your Hubitat's own z-wave exclusion mode is all you need. That's right, you have the power in Hubitat to fix these stubborn z-wave devices, but the first step is to understand that the exclusion process is universal, it is not tied to your old hub, so stop trying to get zwave exclude to work on smartthings, it won't.
I ordered my Z-stick from Amazon, and 20 minutes later discovered I didn't need it... except that I sometimes handle a lot of this stuff, and almost fit into the pro category. So it is up to you, but the Hubitat exclude mode does work...
So here is how exclude works, you enter your Hubitat or z-stick into exclude mode, then activate the button on your device that answers the exclude handshake. For light switches that is usually by toggling the switch on or off. On other devices like a minimote you might have to try different buttons, until you are successful. The minimote lights tell you something is up, some devices flashj an LED in a new way, and others might blink their light or make a noise with their relay. Once you have excluded successfully, you can following pairing instructions.
For some of the older GE z-wave light switches, you will need to exclude them and pair them several times. The exclude is the easy part on these, but the pairing is prone to failure with the Hubitat. You might see it almost pair two or three (or 5 or 6) times before pairing is successful. Pairing is a more complex handshake, and it fails if any noise interferes with the handshake. If Hubitat misses one of the handshake steps, it does not recover, and you must run exclude again.
I had some really stubborn switches that took forever to pair. They would blink like pairing was successful, and hubitat would show something had happened, but it wouldn't complete. And it seemed to fail at different steps in the process. I'm not going to walk you through what those looked like because that was last week I got it done, and I don't feel like re-living it right now.
So don't try excluding from Smartthings, you will be wasting your time. Use Hubitat, or a Z-stick to do your excludes, and them be prepared to repeat your joins several times. It took me hours to figure out that smartthings exclude does nothing, but the first clue is smartthings itself indicated it was failing, but offered the option to "force" the removal which is just deleting it from the app without a proper exclude. Don't be fooled, you MUST do a successful exclude.
For the minimote, I think I hit as button under the door, probably the join button or the - button... But it was easy and worked the first time. Then upon entering join mode, pressing the join button and I was instantly connected.
If your device acts like it is doing nothing when you try to join, then you may not have excluded it yet. It should signal in some way to tell you exclude worked. Only then can you try a join, just be ready to try over and over until you get a clean handshake. We all live in wifi/bluetooth noise zones, and all of that RF noise makes joins take several tries.