Brussels/Bruge and Amsterdam in 4 days?

This is a very personal decision. We’re not like you and we don’t know you. You’ve also given us very little information about your interests and how the rest of your itinerary looks like. By that I mean the days before you leave Copenhagen.
If you go for option 1; What do you want to see in Bruges? Why Brussels? What do you want to see in Amsterdam.
The same for options 2 and 3. How would you fill your days if you decide on option 2 or 3.

This is perhaps not what you want to hear, but there is no one-size-fits-all answer. Only you can decide what feels best for you.

Simply as a practical matter, I suggest you go directly to Bruges from BRU and spend the night there. Then go to Amsterdam by train. If you absolutely must, visit Grand Place in Brussels with or without your luggage, along the way. But I'm saying that you can skip Brussels.

Be careful about discount airlines, because they may not fly to BRU, but to a very inconvenient secondary airport.

BTW, the reason you have the large type is probably because of symbols or punctuation like <, > multiple = or multiple # in your original text. This is related to a standard I don't know much about called "Markdown". You can edit your post if you wish.

Our itinerary prior has no impact which is why it wasn’t mentioned. Just looking for feedback on whether it is practical time wise to try to fit Brussels and or Bruge in over two days on the way to Amsterdam.

To me #1 looks like a lot of moving; #2 & #3 are a pretty much toss up in my mind. If someone had a gun to my head to make a choice, it would #3

happy travels

I asked for your itinerary prior to going to Amsterdam, because to me it would matter if this was for instance on the tail end of a 30-day trip where I changed hotels every 1 or 2 days, or after a 10 day cruise. If it’s the former, I would pick itinerary #3 and stay put in the same hotel for 4 nights.
As you’ve learned from the previous replies, everyone is different and feels different about this. There is no right or wrong answer. All 3 itineraries can be done, it’s a matter of personal preference which one you pick.

1 option- including train time a partial day in Bruge is just not worth it, IMHO. Especially since you would be there mid day with the cruise and Brussels day trippers- and late May will be busy.

2 option- Visiting Brussels is very different than visiting Paris, Rome, Amsterdam... Other than the GrandPlace, the sites are spread out and it takes more time to really get a feel for the city. I've noticed on this forum than many people say don't bother going there, or only 1 day, which is a shame because there are really nice things to see but it takes time. I suspect many don't bother to venture out of the main area. You have to work a bit to "do" Brussels. (My husband has family in Brussels so we have visited a few times, but not as typical tourists.)

3 option- Last summer we had 3 days in Bruge and 3 days in Amsterdam, before time in Brussels. I love Bruge and Brussels, but for your situation, I think I'd feel happy with option #3.

A lot of people on this site prefer Bruges to Brussels. I haven’t done Brussels but we were in Bruges a couple of years ago and loved it. My teenagers liked it better than Paris. It’s small enough that a couple of days would feel like plenty and be able to easily fit in your time frame.