There's your trouble. The power deliverable from a computer's USB port is so little that it's pointless wasting money on building the rest of the product to a decent quality.
Ah gotcha. I think it’s not that uncommon for TVs to have dodgy optical signals but if they’re ok they’re as good as any digital source. I just wondered whether you heard night and day differences because you had £10k of amp and speakers hooked up to it.
Are there any decent USB soundbars for under a monitor? This kind of thing https://smile.amazon.co.uk/Umitive-Computer-Speakers-Compatibility-Anti-slip/dp/B08JTRML6R/
Needs to be USB power and sound input. It all just looks to be cheap, generic stuff that I can find online.