I’m fairly new to crypto and many are promoting the various ERC-20 tokens out there
My question are they all using the same tech and if they are the same just different companies what new innovations do they bring?
Yes generally they use the same tech because all ERC20 operate on the Ethereum blockchain. Different companies, despite the same fundamental structure of the tokens, can offer different use case. Some are stablecoins while some are native to a specific platform. Some can twitch a few things to make them a little unique and make them stand out among the rest. Some examples are uniswap and rndr which have different purposes.
Surely in this case people are just buying into the business plan of the company behind it, I.e Beam or Render and how they use this same tech?
They both use ERC20 which allows for use of smart contracts. Smart contracts are not exclusive to ethereum but it is famously the best for installing smart contracts.