Thanks for the nice mod. A few suggestions if you would be interested:
1. The construction robot is too wide and does not fit in the hatch drone station, it somewhat spoils the impression of the mod, it would be great if it could be slightly reduced, or both robots at once.
2. These drones have the same amount of HP as vanilla, enemies, especially reinforced quickly destroy them, and they are expensive and a little more armor they would definitely not hurt, for example 350 or 500 HP would not be out of balance.
3. Vanilla construction robot has a 50% resistance to electricity, and this robot has no resistance for some reason, is that the idea? Or, it seems that since these robots are better, they should have a little more resistance and stronger.
4. The hull of these robots is significantly different (considering points 3, 4) maybe it would be worth making the recipe a little more expensive, like adding a couple of steel plates or circuits or something.

1. The only solution that I could implement is to make the bots physically smaller, but that will likely bring up it's own set of issues, so I think the only reasonable solution is to just not look too closely.
2. I could increase the durability of the bots, that's quite reasonable for the sake of balance.
3. I am admittedly borrowing code as I am not very familiar with making factorio mods, and was even less familiar with doing so at the time, so I can only imagine that borrowed code was from when bots had no resistances, but I can add the base resistances for the sake of consistency.
4. I find it easy to imagine that the added materials for the fusion bots would come from the exceedingly expensive fusion reactors they're made with, thinking of the bots as less of a bot with a fusion reactor added, and more of an actual fusion of the bot and the reactor.

1. The construction robot is too wide and does not fit in the hatch drone station, it somewhat spoils the impression of the mod, it would be great if it could be slightly reduced, or both robots at once.

You might want to check out Small Robots - Just make the robots a bit smaller, a mod that allows you to scale the size of robots by a factor which you can adjust via start-up setting.

Yes, I already found this mod, it allows you to reduce the size of fusion robots, but only together vanilla ones.
Wow, you released the update so quickly, that's something at least, thanks.

I mean, it's a very simple mod at the end of the day, and I was working up to playing the game again myself.