I started a part-time masters after graduating with my bachelors degree. Due to my day job workload, I abandoned it after 5 years. BUT I don't regret the decisions. Some of the material I learnt, I am using decades later. The fundamentals of CS have barely changed since the 1970s. The topmost level abstractions obviously have changed, and some architectural considerations are very different, e.g. in the 1980s CPUs were slower than memory, now CPUs are orders of magnitude faster than memory. Which in turn impacts upon the foundational algorithms. However, with suitable knowledge you can adapt to such changes.
If you are just looking at it from getting a better paying job perspective, then you will advance further by taking a lucrative job. However, if you are more motivated to broaden your knowledge then a masters is a good choice.