I've just today decided to take a break from the App, but have been using it for nearly 3 years (started in lockdown when my health insurance gave us 6 months free). The only reason I'm pausing is because I've just signed up for a triathlon (a mini mini one!), and want to be outdoors more instead.
We've got a decent spin bike that DH bought secondhand maybe 8-10 years ago, we've also got an old (but decent) treadmill, plus weights etc at home. I used the App loads. As a PP says, I just worked out roughly what my resistance should be (so my bike has 20 resistance levels, Peloton has 100, so if they call for a resistance of 50, I put mine to 10, a resistance of 70 would be 14 etc). My watch monitors heart rate and shows me what exertion levels I'm working at, so although not getting the full metrics, I get enough for my needs. Yes, the ideal would be to have the bike, but I can't justify the additional cost (if it was my only paid-for exercise, and the whole family were using it, yes, that would be good value).
I can also see who else is cycling at the same time as me and can send them high fives (and receive them), although that is basically the extent of the interactivity. I've also used the App for other workouts, and have taken a few of the programmes (I preferred their Couch to 5k to the NHS one). The range of classes and instructors is excellent, I'm really impressed by it.
I think you can probably sign up for a free month to try it out, see what you think. If you've got a Peloton shop near you, you could also get a feel for the differences, and see if you can get a feel for the resistances too.