I had a fluid trainer for a long time that I used off an on over the years, but then got hooked on Sufferfest about 6 or 7 years ago, using an estimated power. I then bought a pair of power meter pedals to find out that my power output wasn't anywhere near that estimate. That only motivated me more. A year later I bought a wheel off smart trainer and started using Zwift as well, and by the end of that winter I was in kick-ass shape. I've been using that off and on over the last few years but in the last month became dedicated to indoor riding again and it feels great.
My advice to you, since it sounds like you can afford it, is to skip the intermediate steps and just buy a smart trainer, preferably a wheel off one. I have the Wahoo Kickr Core myself. Here's a pic of
My setup