I charge 400/h for consulting, specializing in high scale distributed systems. When I'm charging that much I'm not doing the work, companies bring me on for 2 or 3 hours a week to set directions and tech goals as well as solve the problems they've been trying too but can't
You should rise your rate to 2-4x that, and only bother talking to companies that accept such rates (possibly in other regions). If they haggle and you like them / the project, give a symbolic discount like 20%.
I know you probably should request at least 80 eur/h as a freelance but finding a company willing to go for that out of nowhere is impossible. You need really good network to be able to do this. Chance of a company offering a random dude from the internet those rates is near zero. They can hire two cheap devs for that and profit much more, even if those developers will do worse job than you. A lot also depends on the…
In the UK, according to Indeed.com, there are as many .Net jobs as Java. Comparing React with a back-end technology such as .Net is apples to oranges, no?