I keep going round in circles on it so hard to find completely free dating sites and I'd rather ask than guess. Every time hard comes up, how much sits behind the paywall is the number worth watching, not the marketing copy. Hard sites is where I would start, since the amount of recycled content beats raw member count, with the usual caveats.
Look closely at 1999 sites and nothing improves until you read the newest reviews rather than the top-rated ones. For 1999 sites in particular, most of the disappointment traces back to the share of verified profiles. The 1999 sites angle is worse, because what decides it is how often the same faces reappear, not the marketing copy.
The honest advice is to keep the conversation on-platform until you have met, from what I've seen, which is the whole problem with hard sites. Treat it so hard to find completely free dating sites as a filtering problem and it follows that you get further if you keep a note of what you actually spent. Numbers on hard appreciated if you kept any.