I am beginning my final semester of my 4-year undergraduate program, studying Informatics (Computer Science) in Greece, and I expect to graduate this September. I would like to pursue a PhD in the field of astronomy & astrophysics (with a focus on radio astronomy instrumentation), or telecommunications/RF engineering. These two fields have a lot of similarities, especially when it comes to certain aspects of instrumentation.
I am not as interested in Master's studies, because I enjoy conducting research a lot more, which generally tends to prevail in a PhD program. Although pursuing postgraduate studies in Europe is usually hassle-free for European citizens(?), it appears that holding a Master's is a strict requirement to every university in the EU.
However, I've noticed that this is not at all the case with universities in the UK (which should be a bit more accessible compared to e.g. US-based universities, in terms of relocating, visa, paperwork, etc.). This has formed the interest of looking into relevant PhD programs in the UK. Despite my young age (21 years old), I have managed to publish 2 journal papers in the field of radio astronomy and RF engineering, and expect to submit/publish 5 more papers soon.
In case authorship order matters, I've been the 1st author (out of 3) on my first publication and 7th/7 on my second. As for the ones I'm currently preparing, I expect to be 8th/8 on my third paper, 1st/1 on my fourth, 1st/2 on my fifth, 2nd/? on my sixth, and 1st/4 on my seventh. I've been actively working with many coauthors from different institutes around the world, and only 1 publication will consist of coauthors from the lab I've worked with (a different department in my university). I assume this helps promote my experience working with different people from a variety of fields.
I've also worked on countless other projects around the field (including but not limited to education), and I've got over 3 years of industry experience in RF engineering (incl. two full-time jobs, a paid internship in my university, and volunteer work).
Have you got any suggestions on what the best move might be for me? I know most students don't publish until their Master's/PhD's, and different opportunities might be available for me given my experience early on. Considering the lack of a Master's requirement compared to the EU, are UK PhDs ever frowned upon, or are they treated equivalently to EU/US PhDs (given the admission process still favours Master's holders)?
On another note, I've heard that PhD by publication is a thing, but I guess this is more for established researchers late in their career, and as applicable to me. Is this correct, or should it be something to have on my radar?