opinion on applying BSc then doing masters

I don’t know what course you will be doing, thereby “easy” is not really possible to answer.
Personally I did my BSc, got a job for a few years in a hospital (Medical Lab Assistant followed by Associate Practitioner) and then went back to do my MSc (23-24 academic year) and got a Merit but I do think working actually helped me in my Masters as opposed to going back to get my Masters immediately after graduating.
My BSc was in Biomedical Science and my MSc was the same, but I specialised in Clinical Biochemistry.
Masters IMO though was much more intensive than my BSc in terms of workload and time management as by the time March came along, I just wanted it to be over… combining my time spent in the lab, coursework on top and lectures/revising.

i cant choose between bsc chemistry or msci chem with medicinal chem but i think im more keen on doing chemistry so was wondering if it would be difficult to get a job with only bsc

Depends on the route you want to take but in the UK, it is fairly difficult to get your first job, Masters or not just on the basis that experience is king. One example is where my experience is predominantly Clinical Chemistry and Virology (due to the pandemic), haematology, microbiology and cell pathology are typically instant rejections when I apply to them as I have absolutely ZERO experience in them. It took me about a year (and a pandemic) to get my first job as I had no experience in lab procedures, health and safety understanding etc… and you don’t need the Master to go into my field but I would have it as a benefit for getting the Band 6+ jobs.

ohh i didnt know that, thank you for your answer!! i heard from my other friends that they can apply to work at their uni lab during the holidays so im gonna look onto that