I would mirror the sentiments of some other people in this thread as well.
If you're willing to splash that much money on a device, I would hope you intend on keeping it a long while. It would really be prudent to wait for the new Apple Silicon Macs if you can, since this isn't just the case of waiting for a minor update. They're completely overhauling the guts of the machine to the point where it'll make more than a substantial difference, especially for pro users.
It's not really a matter of Intel getting support for the next few years or not. It's just about making sure you have the best, most optimized work experience going forward for the next few years.
"Splash"... lol. It's funny, as it is brutally hard to buy a machine from Apple. They have it figured out so well: just a little more RAM, a little better video card, just a tad more room on the SSD. I have had a lot of the MBPs, from base to pretty loaded. I remember having a 17" (I think). It was heavy, I'm pretty sure the screen alignment would get a little wonky on me. But I was making money in print publishing, had to do most of my own page layout, so that was my go-to for when I wasn't at the ranch. Then my printed mag biz started to wane with the onset of that industry's disruption. I tried to adapt. I had websites since the days when hard coding pages and programs like Hot Dog were around. I can still remember walking into the ISP in my town and paying them for a domain with a check! It was early, but I saw the writing on the wall, and even knowing this, I was never able to make money in "digital". You've got to have a huge audience. I was very vertical and niche, and too small. Anyhow, I then tried to co-brand my websites and print with a YouTube and cable show. I'd send DVDs to local stations in nearby markets, etc. All of that scrubbing of footage, trying to edit in Premiere, the disastrous idiocy of my ineptitude combined with the ever-evolving tech landscape, had me pouring loot into devices of all kinds, especially when it came to kitting out a baby video production set-up.
I always believed the best investment was in yourself, although I am among the least gifted or talented people on earth! I just try and try. I'm getting into old goat territory and as my brain power and skillset's relevance diminishes, I ask myself: do I cut back on the little bit of extra RAM? Should I cheap out on the video card? Will I run out of space on my SSD and continue to be the fool I have always been when it comes to back-up workflow?
"Splash" is a funny word, as you are right: it's a wet hot mess when things go badly, or you see your 1000s in gear depreciating like lightning!
I dished out a ton for my 2011 iMac. I knew video rendering and storage were big so even paid for some help via these forums to replace the Superdrive with another SSD, had them Raid striped 0, etc. The machine was a bear for a long time, and now it sitting in my attic waiting for me to attempt a graphics card swap, as it has become comatose.
I agree about having the best experience, and if that means I must splurge (and I think tax and AC+ is about $700 of that $4K, so is $3300 for the machine that lavish?), I'm thinking time is running out for me why not lol....