If you can find an opto-isolator that is fast enough sure.
Putting both ends of the electronics in an optical usb4 cable would be essentially an opto isolator but the electronics capable of doing it must exist if optical usb4 cables exist. Last time I was trying to find opto-isolators for merely 5gbit usb3 I found nothing.
Do you mean for high speed data?
Or for just power delivery / protection of the CC lines needed for USB-PD?
If you want data, that won’t be trivial. And I believe the cost will be prohibitive.
You can check major parts suppliers and see the speeds available for simple “high speed” opto-isolators. Mouser link, Digikey link. You won’t even get USB 2.0 speeds with those chips.
If you want thunderbolt / USB 4, you’ll be creating the equivalent of what’s inside a fiber optic thunderbolt USB cable. And look at the price of a 40Gbps thunderbolt USB cable. I’m seeing hundreds of dollars. Even slower cables are not cheap. The fiber part of the cable is not that expensive at all, I don’t believe it’s contributing much to the price. Rather it should be the plug ends, the parts you need, where the cost is.
Keep an eye out 
Edit with a bit more context: Volta is working on releasing their Volta MAX cable, which supports USB 3.2 20Gbps and 240w, which is what the Framework 16 runs at. Scroll all the way down on this Kickstarter where they officially announced it a while back: https://www.kickstarter.com/projects/voltamagneticcharger/volta-max-the-cable-for-all-fast-charging-and-data-solutions there is no new information here, but it is the first time Volta or Framework has officially spoken on this. Pictures are same as I’ve released.
Yea, wow. I hope you have some pretty solid insurance for when customers come to you because your cable fucked up their laptop.
Also your Kickstarter has so much marketing bullshit its funny
No mention of any ESD protection, at all. Also not USB certified.
Not even usb4, is that even worth the risk then?
This stuff also doesn’t look any different from the magnetic usb cables you can already get from china and if it doesn’t add any protection you may as well get those, I have one that does usb4 and that was less than 10 bucks (I only tested it, this stuff is way too sketchy for me to actually use it and that is coming from someone that smears liquid metal on everything XD).
I see only one mention of " Volta’s Guarantee and Warranty" in that mile long marketing trash, and no explanation of what they cover. Cool idea if they make it, but I’m so done with kickstarters, specially in this economy where they have a higher temptation to mis-manage the funds and then not deliver on product.
Want to clarify, I am not Volta affiliated and don’t endorse their product. Buying something like this is dangerous. I’m only up-to-date with this product because for a while, it seemed like it was going to be the first 3rd party expansion card, but it is no longer clear if this is still going to happen.
Reddit seems to agree Volta has no credibility https://www.reddit.com/r/UsbCHardware/s/YEGZAynNvI
Has anyone looked into Apple’s Magsafe 3? The official cable might be overpriced at $50USD but its supposedly just a glorified USB-C cable so there wouldn’t be any proprietary firmware to work around. And you’d have charger compatibility with anyone who owns a modern Macbook.
I definitely recall someone looking into it. Trying to make them work with minimal modification, iirc. I think they found that, unsurprisingly, apple seems to have added something into the communication to prevent it from just working with / being compatible with standard USB-C PD. It looks like PD communication, and iirc, parts of PD seem to be there, but it will not start charging USB PD devices.
And one has to note that Apple’s Magsafe is charging only. No data at all. Quite a few people seem to be hoping for charging and data, full high speed thunderbolt data at that, over a single magnetic connection. That is just not possible safely, and also inexpensively. It looks like the cost would be so high that it’s just prohibitive.
~edit~
Here is where a community member was trying to get Magsafe 3 cables to work
Yes, it’s violating USB PD spec a bit, but that can be worked around with a few ICs in the expansion card.
I think that MagSafe 3 is preferable to alternatives, despite overpriced cables, for a couple of reasons:
What magnetic charger did you use, All the ones i can find in this forum have been out of stock for weeks