Thor, first welcome to the forum and to guitar playing. I have a number of somewhat random thoughts on this - let me express them and remember that these are just one person's opinion. Conor and Brian have both given you good advice.
First, one of Leo Fender's true genius's was standardizing everything on his guitars. They are quite literally assembly line produced, and if a manufacturer adheres to Fenders specifications ANY neck will fit ANY body. There is a weird little quirk between tele's and strat's, but it doesn't matter if a neck was made in the Corona plant or Mexico or Seattle or China. It will fit and work. (I'll come back to this).
Second, you are new to guitars and finding it hard to play. Yes they are, I've been working at it for 50 years and they are still hard to play. It is very tempting to want to modify the whole design to make it easier - I'll argue against that if it is remotely possible to play a standard configuration. If you learn on a modified guitar you will always play a modified guitar - that means that Big Lou will be your companion for life. Lots of people with fat fingers and skinny fingers and long fingers and short fingers play guitars with 1-11/16 wide nuts - maybe you can force yourself to learn.
If you do decide to change the neck, then think carefully about the geometry. The standard Fender 1-11/16 neck will have the outside strings about 1/8 from the edge of the fretboard - they should remain there on your new neck. Standard Fender bridges are 2-5/32 spacing - that means the string fan out as they go from nut to bridge - make sure they will do that on your new neck. If one of the outside strings is closer to the edge you risk pulling it off, if it is farther from the edge it will be harder to fret. That means the new neck should be centered to the body and must not have any side to side angle (ie the neck centerline must be perfectly on the body centerline). I check that by laying a straightedge on each side of the neck. Something like this, I want exactly the same spacing at each side of the bridge.
While Brian suggest cutting the pocket, I think I would cut the neck (but not the fretboard). The neck is going to be too wide at the 16th fret (body joint) but you want to keep that fretboard width. If you widen the pocket you will have a ridge between the body and the neck. Yes, you are going to have to fix some finish - find out from Big Lou what they use (oil, lacquer, something else) and repair it on your neck (if its nitro just buy a rattle can and shoot it over the neck heel).
One thing to be really careful of is not to move the neck into or out of the body any amount. The 16th fret should be at the joint - the neck should sit snugly against the end of the pocket. Also you want the overstand and angle to remain the same - normally the outside edge of the fretboard is 3/8 proud of the top and the f/b parallels the top. Once you get the neck into the pocket you will need to do the normal setup adjustments - relief, nut and 12th fret action, intonation. We can help you with this.
So, short story, think carefully about whether you want to go ahead with this. If you do, decide whether you want to modify the neck or the body (or send the neck back and get one built to Fender's specs). Maintain the geometry carefully - both with respect to the center line and the angle and depth. Measure everything multiple times and ask here if you have any questions. Good luck and let us know how it works out.