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Yes, your bike will work. Realistically, any well-maintained bike that can carry a load safely will probably work, whether a used Walmart bike or a $10k custom one. You just may have to adjust some things like slow down on descents.
The question is what is best for you. If you are fine with the bike after you have done a few week-long tours (easily done since your trip is years away), then I say go for it.
The difference is more along the lines of "fine tuning". Let's say you have a basic two wheel drive pickup. It can handle the 1000# load you are carrying OK. It may work a litter harder going up hills, can't handle fast twisty roads super well, or may not be as sure-footed on a muddy gravel road but it works fine overall, you like it, and its paid for. Then one day you got into your buddy's new 2021 4x4 Crew Cab with a strong diesel engine as he carried the same load over the same roads. Even up the steepest mountain road you maintained the speed limit. The drive down the mountain at the speed limit was easy, you didn't even notice the load. With 4 wheel drive, the muddy gravel roads were not much of an issue either. And it cost your buddy $70k. Which truck is better? That is only for YOU to decide.
I have been touring for over 45 years. I have had many good bikes and I have a few "top shelf" quality bikes. They all have toured thousands or tens of thousands miles each. Yes, the very nice bikes have smoother and better handling and are more comfortable after a long day and some handle gravel/mud a lot better. However, as I said before, the "lesser" bikes did fine also.
Your low gear is fine.
You don't mention what wheel set you have. I would say a strong, well-built wheel set is a very nice option to have. I have always had such wheel sets and I have only broken 2 spokes in all these years (one was due to a wreck and the wheel landed on a large rock), never had a cracked rim, very rarely have to true a wheel (like maybe 5 times), etc. I am old school and like more spokes. Yes, I know you can get by on less spokes (what is it now, like down to 16 or some ungodly amount), but to me, if there is a chance you do get a broken spoke, with 36+ spokes, you will have less chance the wheel will become materially out of true and/or "taco'd". While my Rohloff (28 spokes) has less spokes and I have not had any issues, I do worry about it. Again, I am pretty old school.
In regards to the trailer vs. panniers debate, again, do what is best for you. People are usually strongly in one camp or the other. A few nuts like to have both 4 panniers, a rack pack, a handlebar bag, and a trailer but then they need to leave the kitchen sink at home. I would allow an exception is for tandem riders. Try to borrow each setup from a touring buddy and check each system out. Most bike clubs will have members who have one or the other and they are usually willing to loan it to you for the weekend.
If after you test ride each packing system, you will have a better idea as if your bike works for you. My thought is it probably will. If you do get a new bike, consider buying a used one. You can somewhat frequently find used, barely ridden very high quality bikes for 33%-50% off the new price saving you thousands. I can afford any bike, but I am a cheap bastard and want value so I have almost always bought barely used high quality bikes and have never had an issue. Since you have years before your big trip, you could do a "saved search" on eBay for that dream bike that is 50% the new price and when, not if, it pops up, you can buy it then.
Hope you have a great trip!