Clearly your http-1config can’t be used, as you cannot install http-1 binding in OH3.
If only we knew what you did try in OH3, we might be able to help.
Nothing wrong with REGEX. More complex analysis with if-and-but conditions can be carried out in a rule.
Link a plain String to your Thing as well initially, see that the HTML that you expect arrives, before you look at transformation problems.
there are different ways. I am not sure which one the best way could be.
E.g. I am more focused on doing stuff on command line that in the UI. So I would create a shell script and do something like
curl http://URL-here -O - | grep '"uv"' /tmp/abc | sed -e 's/.*value="//' | sed -e 's/".*//'
and call that script from executeComandLine or the exec binding.
This is not tested so some fine tuning might be required.
It‘s also possible to use the JS-Transformation for more complex analysis.
To OP: if you have the regex at hand, I would go with the REGEX transformation. First remove the transformation and link the Channel to a string item. Do you get the raw data? If not, something is wrong with the thing or channel Config. If so, add the regex and see what happens.