Go fornb full straight, then start practising with kapcai first.
Save your time by taking the test twice

Good question, no right answer. In the end, it's up to you. If all goes well, then is fine.
Some tell you B full straight no problem, some tell you B2 then B full.
In some countries, not so lucky, as riders are required to complete a mandatory restricted license period.

Most people I know took B2, then B many years later.
One person I met, took B2, then B full right after that.
One person I know went B full straight after buying a 200kg first naked bike.

If money and time is not a problem, do B2 first, then ride kapcai few years - including clutched kapcai.

Yes. you will be using big bikes for learning and test. you said you no bike experience, does that include bicycle? I mean can you ride a bicycle well?

in that case you should have no problem with jumping on a B full tbh. learning the B2 is hardly challenging for a competent cyclist and you'll probably feel bored of the circuit by your second lesson. with B full you'll have more of a challenge.

but... taking the test and getting your license is one thing, actual riding on the road is another. after you get your B full i suggest carefully choosing a bike that you can manage well.

anyways, what do you intend to ride?

Depends on the destination .. then will consider to ride or not, most of the parking lot for motorbike in Malaysia designed with Kapchai size motorcycle in mind, so please get use to this mentality whenever you going out with 250cc and above bike (also those big scooters even though the cc less than 250 but the size is like a big bike)...

When it come to stealing.. 90% of the thief not steal whole bike, but instead they will take some precious parts and accessories attached into the bike, such as their brake calipers and master cylinders.

i don't know what exactly the riding school's position is on this, but i suspect part of the reasons being its simply easier work for them to "teach" B full to those who already has a B2. There are bound to be cases where people could not even understand the operation of clutches in general or who are not comfortable at cycling to apply for B full only to struggle massively. so from the academy's point of view the less hassle, the better it is. this is why i asked about your own competency on two wheels.

the other issues is that the kapcai you learn with for a B2 is really not much different from a granny bicycle (i would argue that even a mountain bike has more aggressive stance) and it doesn't come with a clutch. again i say that it is barely any harder than riding a bicycle, the kapcai is just different from a clutch bike. the 650s they use for B full training have more in common to the bikes than you would be riding compared to the kapcai. since you are riding partly for the fun or it, you probably be looking at bikes that outclass your B2 a year or two  down the line.

parking is really dependent on where you go. some places like 1U and Empire subang are very good to big bikes so you don't have to worry that much. most people who use big bikes to commute either commute between home and office where  they know the safety of parking, or in malls that have good big bike parking or rarely park it out of sight. if you are talking about a go anywhere bike for general commuting in the city, then i will, as usual, suggest getting a scooter that thieves generally do not target.

honestly, just ditch the school and look for other school that are willing to teach u. Yes i do admit ppl who never rode a bike would become a bit hassle to teach but u already paid them to teach u. Sure its a bit hassle but if customer wanted to do it why not?

from my personal experience... its better for u to take all of them (b full, D license in one go) because u wont have time do re do it when u are getting older or when u are working. for me Big bike got to learn how to properly use clutch and all but if u are keen enough u'll get it in no time. myself need a full year to do B full license not because i cant ride big bike, but because i cant find the time to properly take the test and need to take leave from work just to take the test and what not.

so i say ef the school that dont want to teach u B full and go to other place that are willing.

I would think the main reason school's recommend a safer approach, is for safety reasons. After MCO, the learners' and exam queue is quite backed up. For B-full bike, there's usually just 1 or 2 per school. In some areas, 1 bike is shared among few schools. The last thing they want is anything to happen to that bike. At one time, there will be up to 10 learners riding bikes on the learning ground.

The school may be able to guide you at first, but really the rest is up to you. Here's what I would suggest, get an L first from JPJ. Buy a clutched bike, and go from there.