thunderbolt 2 to USB 3

Older Thunderbolt 1/2 ports on older Macs can only handle the Thunderbolt protocol while the USB-A ports can only handle the USB protocol.

Only the newer 2016+ USB-C Macs have a combination Thunderbolt3/USB3 ports (some may have Thunderbolt4/USB4) which support both the Thunderbolt protocol and the USB protocol.

USB-C is not a protocol, but a connector type which can support Thunderbolt protocol and/or the USB protocol. The device itself will determine which protocol(s) are available. It is very unfortunate they chose such a name for a connector type as is confuses everyone.

You need to determine which protocol your external device is using in order to know which port to use on the older Mac (including the adapter you need to use). If your external device has a lightning bolt icon next to the USB-C port, then it indicates it supports the Thunderbolt protocol. If there is a USB symbol next to the USB-C port, then it indicates the port supports the USB protocol. You can also check the user guide for your device to determine which protocol(s) the device supports.

If I had to guess the majority of devices with USB-C ports will most likely be using the USB protocol, but you need to confirm it to be sure.

I have never seen a Thunderbolt 2-to-USB adapter and the chained adapters you mentioned would probably not work, as TB2 does not support USB nor does it supply USB power.

You could achieve your goal with a Thunderbolt 2 dock although they are getting hard to find since TB3 and TB4 were released. Here's an article from 9to5Mac that reviews a number of TB2 docks -> https://9to5mac.com/2015/10/27/best-thunderbolt-2-dock-for-mac/

And as a much less expensive option than a dock, you should consider a simple, powered USB hub to expand the number of available USB ports.

Amazon's divergent search did cough up ONE dock that is still available, for WAY too much money over a powered USB Hub, but it may appeal to you:

https://www.amazon.com/Elgato-Thunderbolt-Dock-Ethernet-aluminum/dp/B00PAPMSLE/ref=sr_1_6?keywords=thunderbolt+2&qid=1656864594&sr=8-6

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MDB1967 wrote:

Thanks that all makes sense. Kinda makes me wonder why apple did that. Would have preferred another USB port as it seems this lightning ports are only good for video.

At the time it came out, Intel and Apple were heavily promoting the original Thunderbolt and then Thunderbolt 2. That also got really confusing because most Thunderbolt or Thunderbolt 2 setups use the mini-DisplayPort connector which was previously used on some Unibody MBPs only for video. On paper it was great, but the cost of the peripherals (like external drives) was considerably more than USB 3.0, which was fast enough for most users.

It's easy to have 20/20 hindsight.

ThunderBolt-2 disk enclosures and Docks were supposed to be remarkably fast, and everyone would want one, even though they were always sort of expensive.

Then USB hugely upped its game, and USB-3 and ThunderBolt-3 came out, and they put ThunderBolt-2 out of business.