Starting with a relatively simple subtractive software synth that uses primitive "analog" waveforms -- like, say, Tal-Uno-62 (https://tal-software.com/products/tal-u-no-62) -- is probably the best way to play around with learning synthesis. It's a lot harder to create a "bad" sound in a simple subtractive synth, and in something like Tal-Uno-62, there aren't a whole lot of possibly confusing menu options and buttons.

Samples and wavetable synthesis are also relatively easy to get a "good" sound of quickly. Most are structured, architecture wise like a subtractive synthesizer, you just replace the primitive waveform with either a sample, or a bank of digital waveforms.

FM and additive (and spectral and granular) are neat techniques, but IMHO way more finicky to program. (They are also techniques where the software interface is quite welcome! Programming a DX sound in the (free and open source) Dexed VST is quite a bit easier to do than it is on a Yamaha DX7's two-line LCD screen and buttons.)

For the parent poster: I understand that quite a few professionals, particularly in loop / beat oriented music genres (such as hip hop / trap, EDM, and reggaeton) use FL Studio quite a bit! The nice thing about FL Studio is that it has a nice intuitive layout for beat-making. It's what I'd personally recommend for someone just wanting to mess with synthesizer beats. (My personal favorite is Reaper but I don't tend to write beat oriented stuff. :) )

Interesting, for me additive is the most intuitive. I find it easier to visualize sums of sine waves than subtracting harmonics from a more complex waveform (such as a sawtooth), particularly when considering the use of notch or bandpass filters. But that may have a lot to do with my education, which featured a heavy dose of Fourier Transforms and associated techniques.

On the other hand, "simple" additive with relatively few partials is actually pretty easy too. (The Hammond B3 and other tonewheel organs are essentially additive synthesizers.) A lot of software (your Alchemys and Razors) is built on a simplified version of additive too, or uses additive techniques to perform "resynthesis", or has other tools that "simplify" some of the additive editing.