I have a cheap smart trainer and a used stages gen 1 powermeter off ebay. I frequently have issues wih the trainer, erg mode not working, and then turn it off and use it as a dumb trainer. I often wonder if a more expensive one would be better, but I can’t quite justify the costs. But I don’t feel like you’re missing much with the dumb trainer. The power meter fits all my bikes, but I’ve swapped maybe twice in a year for events, and usually it stays on my summer road bike that is on the trainer. I’d probably buy a powermeter rather than an expensive trainer in your situation, I do like being able to train by power outside, and it’s also useful for pacing in group rides.