Ok so let’s say I go up to 3045x pricing, is the extra 45$ for the 3055 worth it?
That depends. I used to own both, but I sold the 3055. It didn't do anything for me that my 3045X (upgraded to 3055X-E) couldn't do. I liked the 3045X better because it doesn't have a fan, so it was quieter.
Technically, the 3055 hardware is superior, but in practice it was the least stable of my 3 bench DMMs. It was still good, but not better (to me), and no thanks to the fan noise.
Now I just have the 3055X-E and the 3065X. I still use both, and if I want it quiet, I use the 3055X-E.
Just keep in mind that if you have a different firmware/hardware range, you won't be able to upgrade the 3045X (at least not yet).
Normally, there's a $100 difference between the two. If you think you'd prefer the 5.5 digits, then I'd spend the extra $45. If you'd prefer it to be quiet, get the 3045X.
The main other thing I would consider is the counts. I do prefer the 5.5 digits (220,000 vs 66,000 on the 4.5 digit meter). The ranges make more sense to me, but YMMV.