I've pieced together a few decent options over the past year, mostly because my wallet couldn't handle another pricey MFA-style course. The Poetry Foundation's website has a solid archive of craft essays and prompts they call 'workshops,' though they're self-guided—you read the material and do the exercises on your own time. Not quite the same as getting live feedback, but the quality of the content is surprisingly high.
For actual interaction, I've had better luck in smaller online writing communities. Sites like Scribophile have dedicated poetry sections where you critique others' work to earn credits to post your own. The feedback can be hit or miss depending on who's online, but I've gotten a couple of really insightful line edits that way. It mimics a workshop environment in a slower, asynchronous format.
I'd also suggest keeping an eye on local libraries and indie bookstores moving online. One near me started a virtual 'Poetry Lab' during the pandemic and just never stopped. It's free, runs bi-weekly, and the facilitator is genuinely engaged. Finding those requires some digging on community bulletin boards or Instagram, but they're out there and often under-attended, which means more airtime for your poems.
University extensions sometimes offer free trial sessions or open houses for their paid workshops, too. I signed up for a notifications list for one and got an email for a single-session 'poetry forms' workshop last fall. It was basically a sampler, but it was well-run and introduced me to a form I still use. The trick seems to be persistent, low-effort searching across different types of platforms, honestly.