Have Facebook ads become more expensive recently?

Yes, Facebook ads have gotten more expensive with average costs to reach users rising around 20% recently due to heavy competition in the auction. For a new campaign focused on driving actual sales, you should plan a starting budget of at least $50 to $100 per day so the algorithm gets enough conversion data to properly optimize and find your buyers.

Facebook ads have become more competitive in many niches but cost varies a lot depending on targeting and creatives I would start with a small test budget gather data and optimize before increasing spend rather than committing a large budget from the beginning

for the crypto products, my campaign costs $35 -$40 per result. I make a profit at this CPM rate. what is your products?

Not really... becuase it depends on lot of factors
geo, niche, no of competitors
and above all optimization of the ad campaigns

as far as i am running ads my cost has only came down over time and not increased.