I'm going to try and give a few answers here.
First point is about Upwork. Upwork is nothing like it used to be and has undergone a stream of changes for the past few months that have made it much, much harder for freelancers to get jobs on the platform. So at the moment, if you have difficulties getting jobs on Upwork, it's probably not entirely due to your profile or portfolio. Just the way it is for even the most experienced, top-rated freelancers there. You can talk about it with other people using Upwork, or even have a look at Upwork's freelancers forum section just to get an idea of the situation.
There are multiple reasons for this (current economic situation, changes in Upwork's algorithms, etc). One big point is that Upwork has been losing money for years. It's absolutely not a profitable business, however it may look. This is actually a more general problem with online businesses. Their business models are shaky and the reason they lose money is that, while they have a lot of users (which is, or at least used to be the big selling point of online businesses), their operating costs are just higher than their revenue. Simple as that. The operating costs for this kind of services are gigantic. Upwork is not the only platform with this problem. So the consequence is that they are now forced (by shareholders) to take action, and they have made changes on the platform to this end, to allegedly make it more profitable (which I doubt it will btw), and these changes have made it much, much worse for freelancers. Not going to get into any more details here, but just keep in mind that if you're not doing well on there, you're not alone. So please focus on finding other ways to get orders.
Regarding specifically your portfolio, while your website in general looks clean and makes it clear from your content that you know what you're talking about, I think your portfolio may be lacking in projects that would better reflect your experience in having developed products in commercial companies, something that clients are often looking for. Do no take this as gratuitous criticism at all, but most of the projects that can be currently seen in your portfolio, apart for the "FT4232H Multi-sensor USB board", while I have no doubt are well designed and functioning, look more like hobbyist projects. And the FT4232H may look a bit too much like a relatively niche, development board. My advice would be to add a few projects that you have developed in your former jobs, and ideally that have become a product. You will probably need to ask permission to add them to your portfolio from your previous employers, but that sure would add value to it.
Also, if your website gets a fair number of visits per month, that's a start. But these days, while I personally tend to still prefer written content to videos (in general), written blogs are unfortunately something a bit of the past. I do not suggest to stop adding content to it, but have you considered making videos as well? That would probably help getting more visibility.