From what i know, theres a potential split to form BTC and BTU, where the main difference is that BTU will have larger block sizes, is this correct?
Does BTU have a fair amount of support?
Yes, you are correct. BU is Segwit plus 2mb blocks. While BC is just segwit.
Yes, BTU has a lot of support 1)from miners, 2)those that are sick and tired of high transaction fees and slow conformation,3)those who have businesses that use bitcoins.
Bitcoin Unlimited was/is a proposed hard fork allowing a dynamic block size. It would basically support continued onchain scaling.
However, Bitcoin Unlimited required 75% of blocks to signal for it for the hard fork to happen. It failed to reach this support, and therefore Bitcoin Unlimited will likely never happen.
However, there is a second proposal with similar goals, entitled Bitcoin Cash. The split that you're mentioning is going to form BTC and BCC (Bitcoin and Bitcoin Cash). Bitcoin Cash will also increase the max block size and support onchain scaling. Bitcoin Cash does not require consensus - it will happen on August 1st regardless of its level of support. I would say that it doesn't have too much support for now, and that a lot of people will sell it first as it's a low-consensus hard fork. Its long-term support is harder to gauge.