Post

No problem

I think the best way to look at it is that it is as a long term project

get a minimum viable synth:

sound source (vco) - plaits is popular and versatile
sound modifier (filter, delay etc) - I'd go for a low pass filter probably - doepfer do quite a few different ones for a reasonable price
modulation source (lfo/env gen/functino gen) - maths - google - 'maths illustrated supplement'
a way to listen - you got it already -4ms module
a way to play - again already got it - Pam's - will do
a decent sized case - already got it - mantis

and ideally a few utility modules - I usually recommend links, kinks, shades, veils (or similar modules - mia instead of shades for example)

and start patching - give it at least a month to learn those modules - as you patch you will work out what you are missing - take note and research and ask questions - buy one of the modules that you are missing, whatever that is -

then buy modules slowly - and save for the next case by sticking (cost of case * hp of module)/ (hp of case) in a jar - when your case is full you will have money for the next one!

you can build up a decent sized modular that will do what you want (and that you will know very well) over as long as you want to take - even a budget of €50-100/month will fill a mantis in a few years - this gives you time to research each new module thoroughly and to learn it back to front in conjunction with your existing modules

in lots of ways this is much better than buying loads of modules at once as that method can be overwhelming and often leads to not knowing your modules that well