A good way to think about it, as several have said. There is no guarantee about the future, and there will be some changing over time - you will probably see your own preferences evolve as you gain experience. The responses also provide a window on some of the brand preferences that play into these discussions. Personally, I have my own and they reflect primarily what our shop carries (and therefore what I get a good price on). But, it is hard to say that one brand is uniformly better than all the rest - there are a number of solid, reliable brands out there. From my perspective, local service availability is more important than brand. Even if you get to the point of servicing all your own gear having a local parts supplier is useful, notwithstanding the pervasive influence of online buying.
A backplate and wing is probably the most modular rig you can choose at this point, and a new recreational diver is well served by doing so. You are also well-served by avoiding 'deluxe' harnesses, and going with a simple (one piece) web harness, without padding. Lots of threads on the BP/W subject on SB.
Dive computer technology continues to rapidly evolve. Today's newest, glitziest triimix computer is tomorrow's eBay special (and I bought two of mine on eBay, at very substantial savings). This area is therefore more challenging to future-proof. I agree with the suggestions to start with a simple, functional, nitrox-enabled, wrist-mounted, non-AI computer that can be used in gauge mode as well as computer mode. From my perspective, an ideal unit will also have a display large enough and uncluttered enough to read underwater, in dim light. I personally like have an elapsed time display that gives me seconds, not just minutes, but that is not as common a feature. When you progress to the point of trimix diving, select another, additional computer at that point. Even if that is only 2 years from now, your choices will probably be somewhat different than they are today. AI is a convenience, not a necessity. User-replaceable batteries are a 'nice-to-have' but not essential, either. I have one trimix computer with a rechargeable battery - works just fine for me. I have two other trimix computers with batteries that are supposed to be replaced by an 'authorized service center', but which I replace myself. That works just fine for me as well.
Most regulators come from the manufacturer ready for 'nitrox' service, e.g. up to 40% O2). Most good regulators can be then cleaned for oxygen service. Don't pay for that before you need it. There are multiple, mid-level regulators available across brand lines that will serve you well. Buy something now that is fully functional for recreational diving, and plan to expand your regulator collection as you move to tec. As several have suggested, start with a configuration that includes two equivalent / identical, well-performing second stages, as well as a long hose for the primary and a bungeed necklace for the alternate, get used to diving that way, and you will never look back.
You can 'future proof' to an extent. But, you should still expect to a) add some gear over time, b) replace some gear as your preferences change, and c) occasionally suffer from pangs of 'woulda, coulda, shoulda' regret. That's the nature of diving.
