Which Mac ?

Apple Silicon Macs

M1 + M2 + M3 MacBook Air, MacBook Pro, iMac, Mac mini

Remember these are intended as entry level Macs, they have great performance, but there are some limitations.
Internally there are two 40Gb Thunderbolt buses just like the 2018 Intel Mac mini, so the same total bandwidth, but externally just two ports.
So you will probably need a Thunderbolt 4 hub to connect more Thunderbolt devices. We use the Anker PowerExpand 5-in-1 Thunderbolt 4 Mini Dock. There are also the OWC Thunderbolt Hub and the Caldigit Element Hub, we have not tested either of these.
Each of these hubs converts one TB port into three.
Only one extra monitor can be connected via USB-C or TB3 in addition to the iMac or MacBook screen or Mac mini HDMI port, probably not an issue.

We have tested YoYotta running on an M1 Apple Silicon Mac mini together with an LTO library and four LTO drives. Archiving and restoring all worked at full speed. Plus it runs cool using a fraction of the power of the older Intel Macs. The 2018 Intel Mac mini ran hot, so Apple Silicon is a great improvement for an archive Mac that is always running.
The Apple Silicon Mac mini can be configured with 10Gb Ethernet, this is recommended for fast connectivity to NAS devices.

M2 Mac mini Pro
Internally there are four 40Gb Thunderbolt buses with four ports externally, so twice the bandwidth for external devices. A great addition to the Apple Mac range and a perfect fit for YoYotta v4 systems with multiple LTO libraries and more than 4 LTO drives.
The Mac mini Pro can be configured with 10Gb Ethernet, this is recommended for fast connectivity to NAS devices.

Mac Studio and Mac Pro
Lots of connectivity and power, get the entry level Max model as the performance of the Ultra isn't needed. However we think it's best to use these Macs with your creative apps, rather than as an archiving machine!

Memory
Apple Silicon Macs with 16GB RAM are fine for YoYotta, however you may want to open Activity Monitor on your current Mac to see how much memory your large YoYotta projects and also other apps are using.

The current YoYotta project is loaded into memory so don't make it too large with hundreds of media snapshots. Instead create a new project.

Summary
Get an Apple Silicon Mac with a minimum of 16GB RAM, 512GB SSD and 10Gb Ethernet. If using high speed storage, running multiple jobs at once and using multiple LTO drives look at more RAM.

All macOS versions since Big Sur will need software drivers for SAS and FibreChannel interface cards and Thunderbolt LTO drives.
Thunderbolt units have a SAS LTO drive inside, so they will need a SAS driver.
Some SAS interfaces might not have Apple Silicon drivers. So you will need to check with the manufacturer and also test all your other hardware with an Apple Silicon Mac to ensure that it all works.

Intel Macs

We do not recommend using an Intel Mac with an internal hard disk drive or Fusion drive. Instead get a Mac with an SSD, not too large as this will be expensive and you don't want to keep any content on the internal drive.
Also avoid the Intel models with i3 and i5 processors.

2018 Mac mini

The 2018 Mac mini is good offload and archive station for YoYotta software. USB3 and Thunderbolt card readers are available for ALEXA, RED and Sony media and the Mac mini has four Thunderbolt 3 ports plus two USB3 ports.
All three models work well with YoYotta software. Get 16GB RAM and 256GB or 512GB SSD. The larger SSD allows for use as a scratch volume.
When working with multiple LTO drives we recommend the i7 model.
With large projects, then the faster i7 with 32GB RAM makes sense.

Connect a Sonnet Thunderbolt chassis with an ATTO SAS or FC card to control one to eight LTO tape drives or an LTO Tape Library. With the Apple adaptor you can also connect Thunderbolt 1 and 2 devices.
Don't forget the optional 10Gb Ethernet port if using a NAS or network with 10Gb connections.

Intel MacPro

For YoYotta workflow then as mentioned above the Apple Silicon Mac mini works well, so the RAM and PCIe card expansion of the MacPro is rarely needed

The 2019 MacPro has thunderbolt ports and internal PCIe slots. Connect LTO drives using an ATTO SAS card in one of the slots or in an external Thunderbolt chassis. We would suggest 32GB RAM.

eGPU

YoYotta Transcode uses a single system GPU, so adding an eGPU doesn't change much. eGPU units only work with Intel Thunderbolt3 Macs. Apple Silicon Macs don't support eGPU. The system GPU in most Macs has plenty of power for resizing and LUT processing used by the Transcode option. The thing that speeds up transcoding is the processor, this is because decoding some codecs and encoding all codecs is a CPU task. This means that the CPU is often the bottleneck. So do not get an eGPU, instead get the best processor option for your Mac.