When placing a blue belt on the output of the tier 3 bucket miner, it can only output on one side of the belt and make the miner start and stop because he is too fast. I it's possible, I suggest the the bucket miner have two output point so half of the trafic came out of each point so it can be collect by two belt that can eventually make them join to use the two side and make the miner work without stoping and starting every half second

"I suggest the the bucket miner have two output point"
Yeah me too. Sadly miner outputs can't be separated(easily).
However: You can use a chest and stack inserters or robots

How is it possible to unload a single chest onto two full blue belts using stack inserters? You can only get 3 inserters around the chest. That can't even fill one blue belt. Even Tier 2 drill fills a chest faster than I can unload it. Best I could do was have the drill empty into one side of a blue belt while a stack inserter pulled what it could to another belt and then combined the two. But that still wasn't quite fast enough for the Tier 2. Tier 3 is just a waste to build.

1) consider using (Mini-)Loaders
2) consider Bigger chest(footprint wise)/Warehousing mods
Both options can be used together ;)

Don't output into a chest. Output into a railcar. If you align the railcar right you can get 10 stack unloaders around the railcar.

Solution: Warehouse. There is a warehouse mod that makes a building that is essentially a giant chest. The storehouse is 3x3 and the warehouse is 6x6 I believe. Both are enough room for loaders, multiple belts or just use tons of bots to load elsewhere.

Edit:Noticed you already suggested this.

Anyway, amazing mod. Thanks for taking it over. I was using the TA Miners for a bit but hated how the designs clashed with the rest of the aesthetic.