@tmarzetta In the Blackmagic support forums, the Intensity Shuttle shows as being Intel Mac only: https://forum.blackmagicdesign.com/viewtopic.php?f=3&t=129564&p=716891&hilit=+intel+Macs+only+#p716891
If you already have an Intensity Shuttle, you could opt to purchase a used Intel based Mac to setup a fairly low cost capture workstation (as you've already mentioned). You may already know that macsales.com is a good vendor for new and used Macs.
If using your M3 MacBook Pro Max, go with the Intenstiy Pro 4K ($285.00) in an expansion chasis, the UltraStudio HD Mini ($649.00), or the UltraStudio 4K Mini ($1,165.00). When capturing VHS or Hi8 via BD's Media Express software, there are settings to upconvert to HD on the fly while capturing; however, that's just a software upconversion. I'd still capture to an SD resolution using ProRes 422 or ProRes 422 HQ and then upconvert that with Topaz Video afterward. If there's no budget for Topaz, there's Detail-preserving Upscale in After Effects - but Topaz is well worth it. In the Blackmagic Design Media Express app, it's going to show as "525i59.94 NTSC" for the project video format. If capturing PAL, the setting is "625i50 PAL". I'd need to double-check this, but I think the resulting NTSC capture is 486i instead of 480i.
Pictured: Blackmagic Design Media Express Project Video Format for NTSC Pictured: Blackmagic Design Media Express Project Video Format for PAL
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