I'm in a somewhat similar situation and had been considering a Masters degree for several years before finally giving up on the idea. I wish the author luck, and from what I saw doing my research I expect he'll need quite a lot of it if he wants to be successful.

The challenges I've seen with masters programs fall into a few broad categories:

First, few admissions processes seem to really be designed to accommodate returning students, especially those who have been out of academia for a long time. Most schools want recommendation letters, and expect at least one or two of those to come from academia. You can get professional recommendations, and it seems like having one or two is a benefit, but a lack of any academic recommendations seems to put you in a bad position for admissions.

It's also quite hard to make up for other admissions blockers if you've been out of school for a while. If you have missing prerequisites or a low GPA your out of luck. Finding out you need more research experience seems to be another significant blocker, although I've heard of people in industry successfully volunteering time working with researchers to get experience ahead of Masters applications, so that could be possible in some circumstances.

Overall, it seems that unless you finished up your undergrad program already planning for a masters degree, you're going to be stuck with some semesters of taking undergrad courses as a non-degree seeking student to fill in missing prerequisites, get the relationships with instructors that you'll need for referrals, and possibly get documented evidence to counter questions about a low GPA.

That ties into the second problem: Most programs lack the flexibility they'd need to provide real value to experienced developers. Masters programs could have a lot to offer experienced developers without a formal CS background, but they are largely designed for people with little work experience, and the requirements involve a lot of courses that are going to be a waste of time for someone with substantial industry experience. The vast majority of masters programs have some required courses designed to prepare people for industry that are going to be superfluous to anyone with substantial experience. If you have a lot of missing prerequisites on your transcript that can be even worse as you're also required to take unnecessary courses outside of a degree program to even be considered.

The lack of flexibility also manifests in another problem: The abysmal state of online programs. There are a lot of bad masters programs out there, but even the good ones aren't going to be good for everyone. Every school has a machine learning and cyber security masters track, and if you have interests outside of those areas then you're going to be substantially limiting the already narrow choices of schools that have a decent curriculum that you can get admitted to. At least for my areas of interest, few of those had quality online programs. That said, suppose you do find an online program that aligns with your interest, the online education system these days requires complete submission to a ludicrous panopticon of the shittiest and most invasive software imaginable. If you like in-person learning or you don't want your life for the next several years to be massively and shamelessly exploited by proctoring spyware, then you better be prepared to relocate, and hope that your manager is okay with you being gone in the middle of the day a few days a week, because few of the best programs offer evening or weekend course options.

After looking at the state of masters programs, I personally decided the easier thing to do was to simply continue self learning, making contacts with researchers who are working in areas that interest me, and work to establish myself enough to have a chance to collaborate independently on research and find ways to get into the kind of work I'm interested in without formal credentials.