As pp said, "counsellor" is not a protected title, so technically you don't need any qualification to call yourself one.
However, to register with the BACP or the NCPS you need a minimum of a level 4 diploma that includes 100 hours of seeing clients.
Most level 4 courses require 20 hours of your own personal therapy, I'm not sure if this is a BACP/NCPS requirement, but I know the charity I work for will automatically reject any applicants who have taken a course without the personal therapy element.
Employed jobs will want you to be registered with some sort of body. The BACP or UKCP are probably the most popular.
There are costs to consider aside from course fees including the time and cost of personal therapy, supervision and the voluntary placement hours you'll have to build up.
The amount of supervision and personal therapy that's required is very course dependent, often with higher level qualifications requiring more than lower. For example, a L4 Diploma might ask for 20 hrs whereas a BSc might ask for 50.
In NI the NHS counselling jobs tend to lean towards CBT and so require BABCP registration. Queens offer a masters but have quite specific entry requirements.
It would be good to get some clarity on what modality you're interested in studying, as this will really help you choose your course.
Employed counselling jobs are few and far between and tend to be poorly paid as they're often in charities.
Some counsellors go into private practice as a self employed counsellor. Generally it takes 2-3 years to build a sustainable client base and generate a decent income, so this is almost always done alongside another part time job for a while.
Private practice can be competitive depending on what part of the country you're in, what demand is like there and how many counsellors are already working in that area etc. There can also be big fluctuations in client numbers.
BetterHelp have largely dominated the online market, so all of those geographic influences do matter.
You need a whole other set of skills to be self employed, it can be lonely and you need to be good at marketing and reasonably business minded.
There's no guaranteed job at the end of the counselling qualification. Some do it full time, but a significant number of people see a few clients a week alongside another job or have done a sideways move into something that utilises the skills.