I'm considered this idea myself, it's very hard to find good quality Christmas lights these days, it's all made in China cheap garbage. It's too bad because LED tech itself is good, but the consumer strings use the cheapest possible LED modules are are just overall badly designed. I had a 2 sets completely die on me after only a few years of use. I find they are also not as bright as the incandescents.
One thing I'd love to look into one day is making my own using addressable LED modules. They would need to be permanently mounted on the house in such a way that they don't get direct sun light, as no matter what that will start to fade plastic after a while. I'm thinking they could be mounted directly under the soffits. Bulbs could still extend out but they could have replaceable plastic covers so when those do fade over time you can replace just the covers. Some of the cheap ones actually do already work like this, so could use the same kind of caps. The thing I'd want too is to make each LED addressable, using a standard protocol. (no app crap, just a basic serial protocol that can be ran from a raspberry pi). This would let me change the colours as I see fit, maybe have them animate etc. Could even have them do stuff for different seasons.
I don't know enough about designing this sort of thing though, like the electronics and coding I could figure out, but the actual plastic molding and the actual physical design would be out of my field of knowledge.
The next best thing is to just look into commercial lightning, they are supposedly good to stay year round and each bulb is 120v and has it's own converter, so you're not having to deal with 1 LED going bad and taking out a whole section.
This is one site I found that sells commercial lights:
https://www.dekralite.com/
I'm tempted to buy at least a pack of bulbs, just to see if I like them, and if I do I will buy more, along with strings. The main thing I always watch out for with LED is that they properly bridge rectify and smooth them out. Unfortunately no company seems to really advertise this. So you pretty much need to buy and see for yourself. I have successfully modified some strings to at least put all the LEDs on the same polarity, then I plug it into a FULL BRIDGE RECTIFIER. It still flickers but at 120hz instead of 60 so it's not as hard on the eyes. Some sets don't have that flicker out of the box and don't require modding though, so at least some of them get it right.