Dumb trainer or smart meter


I’m new here, and im new too as a cyclist (only 7 months), i want to ask which one better for me to improve my power as a cyclist.
Right now, I’m using a dumb trainer with powermeter on my bike. I usually riding outside, but for 3 months i was busy so i bought a dumb trainer and power meter too help me cycling in my home with zwift (3months already using power meter) , but after riding using zwift, i feel like i need smart trainer to feel more realistic on zwift, my question is, if my goals to improve my power, do i really need smart trainer, or my setup right now is more than enough to run zwift and do some workout? right now i have to choose subscription xert for 12months, or buy a old smart trainer (old wahoo kickr gen 1), i dont want to spend so much money for my indoor setup TBH, thats why i need help to decide, and i need structure workout so im not only riding for fun when indoor