FWIW i too was in the same position as many of y’all above a few years ago…started in euro, got caught up in the gas, and luckily fell into R*S Euroserge as part of that. The sound got me hooked, and then the learning about patch programming etc coupled with my waning love affair with euro convinced me to abandon euro and commit to 4U banana jacks.
I will editorialize that as someone who at one point had almost 12U worth of eurorack R*S serge modules and plenty of tip-top stackables, it REALLY is NOT THE SAME as patching on a 4U system with bananas. I can’t intellectually explain why, other than to say that it just doesnt fell the same. and, I dont regret abandoning euro for one second. only regret is that I havent yet sold all of my euro stuff (will still hold onto some sequencing modules probably and mannequins and monome modules to help interface)
now, in terms of which way to go, I think as a beginner, going with a fully “realized” full panel thats already been well thought out is the way to go. this means probably an RS La Bestia or Mantra panel, or LW sing to me Panel (or other current "voice"panel he may be offering) or other used STS voice type panels that often show up used. I say this because unlike eurorack, no one module in serge necessarily fills one role so the approach to putting together a panel will probably be different than what youre used to, and you might hin somehintg like, oh, i only have a VCFQ/VCFS module, I need another filter, but after experience reealize that your SSH can serve diltereing duties, or DUSG can filter, or etc etc etc. The point is that The full panels dont have everything, but they are excellent for learning and you can still make great stuff with it. Then once you learn what you cant do with the panel, you can go back and design a custom panel or build out a 4x4 system, or whatever.
Anywho. my two cents. just to say, go for it. you wont regret. theres no wrong choices. happy to answer any questions you might have